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YALE  UNIVERSITY 

MRS.  HEPSA  ELY  SILLIMAN 

MEMORIAL  LECTURES 


In  the  year  1883  a  legacy  of  eighty  thousand  dollars  was  left  to  the 
President  and  Fellows  of  Yale  College  in  the  city  of  New  Haven,  to  be  held 
in  trust,  as  a  gift  from  her  children,  in  memory  of  their  beloved  and 
honored  mother,  Mrs.  Hepsa  Ely  Silliman. 

On  this  foundation  Yale  College  was  requested  and  directed  to  establish 
an  annual  course  of  lectures  designed  to  illustrate  the  presence  and  prov- 
idence, the  wisdom  and  goodness  of  God,  as  manifested  in  the  natural  and 
moral  world.  These  were  to  be  designated  as  the  Mrs.  Hepsa  Ely  Silliman 
Memorial  Lectures.  It  was  the  belief  of  the  testator  that  any  orderly 
presentation  of  the  facts  of  nature  or  history  contributed  to  the  end  of 
this  foundation  more  effectively  than  any  attempt  to  emphasize  the  elements 
of  doctrine  or  of  creed ;  and  he  therefore  provided  that  lectures  on  dogmatic 
or  polemical  theology  should  be  excluded  from  the  scope  of  this  foundation, 
and  that  the  subjects  should  be  selected  rather  from  the  domains  of  natural 
science  and  history,  giving  special  prominence  to  astronomy,  chemistry, 
geology,  and  anatomy. 

It  was  further  directed  that  each  annual  course  should  be  made  the  basia 
of  a  volume  to  form  part  of  a  series  constituting  a  memorial  to  Mrs. 
Silliman.  The  memorial  fund  came  into  the  possession  of  the  Corporation 
of  Yale  University  in  the  year  1901;  and  the  present  volume  constitutes 
the  fourteenth  of  the  series  of  memorial  lectures. 


SILLIMAN  MEMORIAL.  LECTURES 
PUBLISHED  BY  YALE  UNIVERSITY  PRESS 


ELECTRICITY  AND  MATTER.  By  Joseph  John  Thomson,  d.s  c, 
LL.D.,  PH.D.,  F.R.S.,  Fellow  of  Trinity  College  and  Cavendish  Professor  of 
Experimental  Physics,  Cambridge  University. 

{Fourth  printing.)     Price  $1.50  net. 

THE  INTEGRATIVE  ACTION  OF  THE  NERVOUS  SYSTEM.  By 
Charles  S.  Sherrington,  d.sc,  m.d.,  hon.  ll.d.  tor.,  f.r.s.,  Holt  Pro- 
fessor of  Physiology,  University  of  Liverpool. 

{Fifth  Printing.)     Price  $5.00  net. 

RADIOACTIVE  TRANSFORMATIONS.     By  Ernest  Rutherford,  d.sc, 
LL.D.,  F.R.S.,  Macdonald  Professor  of  Physics,  McGill  University. 
Price  $5.00  net. 

EXPERIMENTAL  AND  THEORETICAL  APPLICATIONS  OF  THER- 
MODYNAMICS TO  CHEMISTRY.  By  Dr.  Walter  Nernst,  Professor 
and  Director  of  the  Institute  of  Physical  Chemistry  in  the  University  of 

^^^^^^'  Price  $1.50  net. 

PROBLEMS  OF  GENETICS.  By  William  Bateson,  m.a.,  f.r.s,.  Director 
of  the  John  Innes  Horticultural  Institution,  Merton  Park,  Surrey, 
England.  {Second  printing.)     Pnce  $5.00  net. 

STELLAR   MOTIONS.     With    Special   Reference   to   Motions  Determined 
by  Means  of  the  Spectrograph.     By  William  Wallace  Campbell,  sc.d., 
LL.D.,  Director  of  the  Lick  Observatory,  University  of  California. 
{Second  printing.)     Price  $5.00  net. 

THEORIES  OF  SOLUTIONS.  By  Svante  Arrhenius,  ph.d.,  sc.d.,  m.d., 
Director  of  the  Physico-Chemical  Department  of  the  Nobel  Institute, 
Stockholm,  Sweden. 

{Third  printing.)     Price  $3.00  net. 

IRRITABILITY.  A  Physiological  Analysis  of  the  General  Effect  of 
Stimuli  in  Living  Substances.  By  Max  Verworn,  m.d.,  ph.d.,  Professor 
at  Bonn  Physiological  Institute. 

{Second  printing.)     Price  $5.00  net. 

PROBLEMS  OF  AMERICAN  GEOLOGY.  By  William  North  Rice, 
Frank  D.  Adams,  Arthur  P.  Coleman,  Charles  D.  Walcott,  Walde- 

MAR  LiNDGREN,   FREDERICK  LESLIE  RaNSOME,  AND  WiLLIAM  D.  MATTHEW. 

{Second  printing.)     Price  $5.00  net. 
THE  PROBLEM  OF  VOLCANISM.     By  Joseph  Paxson  Iddings,  ph.b., 
^^•^*  {Second  printing.)     Price  $5.00  net. 

ORGANISM    AND    ENVIRONMENT    AS    ILLUSTRATED    BY    THE 
PHYSIOLOGY   OF   BREATHING.    By   John   Scott   Haldane,   m.d., 
LL.D.,  F.R.S.,  Fellow  of  Ncw  College,  Oxford  University. 
{Second  printing.)     Price  $1.25  net. 


A  CENTURY  OF  SCIENCE 
IN  AMERICA 


AV^'.El^o^^  -e. 


l/ t),  tJyl^L-^^'t^'^^'^-'-^t^Ct''-i^ 


CENTURY  OF  SCIENCE 

IN  AMERICA 

WITH  SPECIAL.  REFERENCE  TO  THE 

AMERICAN  JOURNAL  OF  SCIENCE 

1818-1918 

BY 

EDWARD  SALISBURY  DANA  •  CHARLES  SCHUCHERT 

HERBERT  E.  GREGORY  •  JOSEPH  BARRELL  •  GEORGE  OTIS  SMITH 

RICHARD  SWANN  LULL  •  LOUIS  V.  PIRSSON 

WILLIAM  E.  FORD  •  R.  B.  SOSMAN  •  HORACE  L.  WELLS 

HARRY  W.  FOOTE  •  LEIGH  PAGE  •  WESLEY  R.  COE 

AND  GEORGE  L.  GOODALE 


NEW  HAVEN 

YALE  UNIVERSITY  PRESS 

LONDON  •  HUMPHREY   MILPORD  •  OXFORD   UNIVERSITY   PRESS 

MDCCCCXVIII 


COPYEIGHT,  1918,  BY 
YALE  UNIVERSITY  PRESS 


^ 


127 

C3 


PREFATORY  NOTE 

The  present  book  commemorates  the  one-hundredth  anniversary 
of  the  founding  of  the  American  Journal  of  Science  by  Benjamin 
Silliman  in  July,  1818.  The  opening  chapter  gives  a  somewhat 
detailed  account  of  the  early  days  of  the  Journal,  with  a  sketch 
of  its  subsequent  history.  The  remaining  chapters  are  devoted 
to  the  principal  branches  of  science  which  have  been  prominent 
in  the  pages  of  the  Journal.  They  have  been  written  with  a 
view  to  showing  in  each  case  the  position  of  the  science  in  1818 
and  the  general  progress  made  during  the  century;  special 
prominence  is  given  to  American  science  and  particularly  to  the 
contributions  to  it  to  be  found  in  the  Journal's  pages.  Refer- 
ences to  specific  papers  in  the  Journal  are  in  most  cases  included 
in  the  text  and  give  simply  volume,  page,  and  date,  as  (24,  105, 
1833)  ;  when  these  and  other  references  are  in  considerable 
number  they  have  been  brought  together  as  a  Bibliography  at 
the  end  of  the  chapter. 

The  entire  cost  of  the  present  book  is  defrayed  from  the 
income  of  the  Mrs.  Hepsa  Ely  Silliman  Memorial  Fund,  estab- 
lished under  the  will  of  Augustus  Ely  Silliman,  a  nephew  of 
Benjamin  Silliman,  who  died  in  1884.  Certain  of  the  chapters 
here  printed  have  been  made  the  basis  of  a  series  of  seven  Silli- 
man Lectures  in  accordance  with  the  terms  of  that  gift.  The 
selection  of  these  lectures  has  been  determined  by  the  conveni- 
ence of  the  gentlemen  concerned  and  in  part  also  by  the  nature 
of  the  subject. 


TABLE  OF  CONTENTS 

Prefatory  Note  vii 

I.     The  American  Journal  of  Science  from  1818  to  1918. 

Edward  Salisbury  Dana 13 

II.    A  Century  of  Geology :   The  Progress  of  Historical 

Geology  in  North  America.     Charles  Schuchert      60 

III.  A  Century  of  Geology:    Steps  of  Progress  in  the 

Interpretation   of   Land   Forms.      Herbert   E. 
Gregory 122 

IV.  A  Century  of  Geology  (continued)  :    The  Growth 

of    Knowledge    of    Earth    Structure.      Joseph 
Barren 153 

y.    A    Century   of    Government    Geological    Surveys. 

George  Otis  Smith 193 

YI.     On  the  Development  of  Vertebrate  Paleontology. 

Eichard  Swann  Lull 217 

VII.    The  Kise  of  Petrology  as   a   Science.    Louis   V. 

Pirsson 248 

VIIL     The   Growth   of  Mineralogy   from   1818   to  1918. 

William  E.  Ford 268 

IX.  The  Work  of  the  Geophysical  Laboratory  of  the 
Carnegie  Institution  of  Washington.  E.  B. 
Sosman 284 

X.  The  Progress  of  Chemistry  during  the  Past  One 
Hundred  Years..  Horace  L.  Wells  and  Harry 
W.  Foote 288 

XL    A  Century's  Progress  in  Physics.    Leigh  Page 335 

XII.    A  Century  of  Zoology  in  America.    Wesley  E.  Coe    391 

XIIL     The  Development  of  Botany  since  1818.     George  L. 

Goodale 439 


PORTRAITS 


Benjamin  Silliman Frontispiece 

rrom  a  painting  by  G.  S.  Hubbard,  Esq.,  in  possession  of 
Miss  Henrietta  W.  Hubbard 

Benjamin  Silliman,  Jr opposite  page     28 

James  D.  Dana *  *  ' '  36 

Edward  S.  Dana *'  *'  48 

Wolcott  Gibbs ''  *'  52 

James  Hall * '  "  84 

G.  K.  Gilbert * '^  '*  140 

Edward  Hitchcock '*  '*  156 

O.C.  Marsh *'  ''  232 

F.  V.  Hayden ''  ''  196 

J.W.Powell ''  ''  204 

Clarence  King ''  **  208 

George  J.  Brush "  '*  276 

J.  Willard  Gibbs "  ''  324 

H.A.Newton ''  ''  336 

James  Clerk  Maxwell '*  *'  348 

Louis  Agassiz *  *  *  *  404 

Thomas  H.  Huxley *'  "  410 

A.  E.  Yerrill ''  ''  412 

Asa  Gray *  *  * '  444 

Charles  Darwin ^  *  *  *  452 


A  CENTURY  OF  SCIENCE 
IN  AMERICA 

I 

THE  AMERICAN  JOURNAL.  OF  SCIENCE 
FROM  1818  TO   1918 

By  EDWARD   S.  DANA 

Introduction, 

IN  July,  1818,  one  hundred  years  ago,  the  first  number 
of  the  American  Journal  of  Science  and  Arts  was 
given  to  the  public.  This  is  the  only  scientific 
periodical  in  this  country  to  maintain  an  uninterrupted 
existence  since  that  early  date,  and  this  honor  is  shared 
with  hardly  more  than  half  a  dozen  other  independent 
scientific  periodicals  in  the  world  at  large.  Similar  pub- 
lications of  learned  societies  for  the  same  period  are  also 
very  few  in  number. 

It  is  interesting,  on  the  occasion  of  this  centenary,  to 
glance  back  at  the  position  of  science  and  scientific  liter- 
ature in  the  world's  intellectual  life  in  the  early  part  of 
the  nineteenth  century,  and  to  consider  briefly  the  mar- 
velous record  of  combined  scientific  and  industrial  prog- 
ress of  the  hundred  years  following — subjects  to  be 
handled  in  detail  in  the  succeeding  chapters.  It  is  fitting 
also  that  we  should  recall  the  man  who  founded  the 
Journal,  the  conditions  under  which  he  worked,  and  the 
difficulties  he  encountered.  Finally,  we  must  review,  but 
more  briefly,  the  subsequent  history  of  what  has  so  often 
been  called  after  its  founder,  *^Silliman's  Journal." 

The  nineteenth  century,  and  particularly  the  hundred 
years  in  which  we  are  now  interested,  must  always  stand 
out  in  the  history  of  the  world  as  the  period  which  has 


14  A  CENTURY  OF  SCIENCE 

combined  the  greatest  development  in  all  departments  of 
science  with  the  most  extraordinary  industrial  progress. 
It  was  not  until  this  century  that  scientific  investigation 
used  to  their  full  extent  the  twin  methods  of  observation 
and  experiment.  In  cases  too  numerous  to  mention  they 
have  given  us  first,  a  tentative  hypothesis ;  then,  through 
the  testing  and  correcting  of  the  hypothesis  by  newly 
acquired  data,  an  accepted  theory  has  been  arrived  at; 
finally,  by  the  same  means  carried  further  has  been 
established  one  of  nature 's  laws. 

Early  Science. — Looking  far  back  into  the  past,  it 
seems  surprising  that  science  should  have  had  so  late  a 
growth,  but  the  wonderful  record  of  man's  genius  in  the 
monuments  he  erected  and  in  architectural  remains 
shows  that  the  working  of  the  human  mind  found  expres- 
sion first  in  art  and  further  man  also  turned  to  litera- 
ture. So  far  as  man's  thought  was  constructive,  the 
early  results  were  systems  of  philosophy,  and  explana- 
tions of  the  order  of  things  as  seen  from  within,  not  as 
shown  by  nature  herself.  We  date  the  real  beginning  of 
science  with  the  Greeks,  but  it  was  the  century  that  pre- 
ceded Aristotle  that  saw  the  building  of  the  Parthenon 
and  the  sculptures  of  Phidias.  Even  the  great  Aristotle 
himself  (384-322  B.  C.)  though  he  is  sometimes  called  the 
''founder  of  natural  history,"  was  justly  accused  by 
Lord  Bacon  many  centuries  later  of  having  formed  his 
theories  first  and  then  to  have  forced  the  facts  to  agree 
with  them. 

The  bringing  together  of  facts  through  observation 
alone  began,  to  be  sure,  very  early,  for  it  was  the  motion 
of  the  sun,  moon,  and  stars  and  the  relation  of  the  earth 
to  them  that  first  excited  interest,  and,  especially  in  the 
countries  of  the  East,  led  to  the  accumulation  of  data  as 
to  the  motion  of  the  planets,  of  comets  and  the  occur- 
rence of  eclipses.  But  there  was  no  coordination  of 
these  facts  and  they  were  so  involved  in  man's  super- 
stition as  to  be  of  little  value.  In  passing,  however,  it  is 
worthy  of  mention  that  the  Chinese  astronomical  data 
accumulated  more  than  two  thousand  years  before  the 
Christian  era  have  in  trained  hands  yielded  results  of  no 
small  significance. 

Doubtless  were  full  knowledge  available   as  to   the 


AMERICAN  JOURNAL  OF  SCIENCE  16 

science  existing  in  the  early  civilizations,  we  should  rate 
it  higher  than  we  can  at  present,  but  it  would  probably 
prove  even  then  to  have  been  developed  from  within,  like 
the  philosophies  of  the  Greeks,  and  with  but  minor 
influence  from  nature  herself.  It  is  indeed  remarkable 
that  dowm  to  the  time  with  which  we  are  immediately  con- 
cerned, it  was  the  branches  of  mathematics,  as  arithmetic 
and  geometry  and  later  their  applications,  that  were  first 
and  most  fully  developed :  in  other  words  those  lines  of 
science  least  closely  connected  with  nature. 

Of  the  importance  to  science  of  the  Greek  school  at 
Alexandria  in  the  second  and  third  centuries  B.  C,  there 
can  be  no  question.  The  geometry  of  Euclid  (about  300 
B.  C.)  was  marvelous  in  its  completeness  as  in  clearness 
of  logical  method.  Hipparchus  (about  160-125  B.  C.) 
gave  the  world  the  elements  of  trigonometry  and  devel- 
oped astronomy  so  that  Ptolemy  260  years  later  was  able 
to  construct  a  system  that  was  well-developed,  though  in 
error  in  the  fundamental  idea  as  to  the  relative  position 
of  the  earth.  It  is  interesting  to  note  that  the  Almagest 
of  Ptolemy  was  thought  worthy  of  republication  by  the 
Carnegie  Institution  only  a  year  or  two  since.  This 
great  astronomical  work,  by  the  way,  had  no  successor 
till  that  of  the  Arab  Ulugh  Bey  in  the  fifteenth  century, 
which  within  a  few  months  has  also  been  made  available 
by  the  same  Institution. 

To  the  Alexandrian  school  also  belongs  Archimedes 
(287-212  B.  C),  who,  as  every  school  boy  knows,  was  the 
founder  of  mechanics  and  in  fact  almost  a  modern  physi- 
cal experimenter.  He  invented  the  water  screw  for  rais- 
ing water;  he  discovered  the  principle  of  the  lever, 
which  appealed  so  keenly  to  his  imagination  that  he 
called  for  a  -rrov  (ttw,  or  fulcrum,  on  which  to  place  it  so  as 
to  move  the  earth  itself.  He  was  still  nearer  to  modern 
physics  in  his  reputed  plan  of  burning  up  a  hostile  fleet 
by  converging  the  sun's  rays  by  a  system  of  great 
mirrors. 

To  the  Romans,  science  owes  little  beyond  what  is 
implied  in  their  vast  architectural  monuments,  buildings 
and  aqueducts  which  were  erected  at  home  and  in  the 
countries  of  their  conquests.  The  elder  Pliny  (23-79 
A.  D.)  most  nearly  deserved  to  be  called  a  man  of  science, 


16  A  CENTURY  OF  SCIENCE 

but  his  work  on  natural  history,  comprised  in  thirty- 
seven  volumes,  is  hardly  more  than  a  compilation  of 
fable,  fact,  and  fancy,  and  is  sometimes  termed  a  collec- 
tion of  anecdotes.  He  lost  his  life  in  the  *^  grandest 
geological  event  of  antiquity,''  the  eruption  of  Vesuvius, 
which  is  vividly  described  by  his  nephew,  the  younger 
Pliny,  in  **one  of  the  most  remarkable  literary  produc- 
tions in  the  domain  of  geology''  (Zittel). 

With  the  fall  of  Rome  and  the  decline  of  Roman  civ- 
ilization came  a  period  of  intellectual  darkness,  from 
which  the  world  did  not  emerge  until  the  revival  of  learn- 
ing in  the  fifteenth  and  sixteenth  centuries.  Then  the 
extension  of  geographical  knowledge  went  hand  in  hand 
with  the  development  of  art,  literature,  and  the  birth  of  a 
new  science.  Copernicus  (1473-1543)  gave  the  world  at 
last  a  sun-controlled  solar  system;  Kepler  (1571-1630) 
formulated  the  laws  governing  the  motion  of  the  planets ; 
Galileo  (1564-1642)  with  his  telescope  opened  up  new 
vistas  of  astronomical  knowledge  and  laid  the  founda- 
tions of  mechanics;  while  Leonardo  da  Vinci  (1452-1519), 
painter,  sculptor,  architect,  engineer,  musician  and  true 
scientist,  studied  the  laws  of  falling  bodies  and  solved 
the  riddle  of  the  fossils  in  the  rocks.  Still  later  Newton 
(1642-1727)  established  the  law  of  gravitation,  developed 
the  calculus,  put  mechanics  upon  a  solid  basis  and  also 
worked  out  the  properties  of  lenses  and  prisms  so  that 
his  Optics  (1704)  will  always  have  a  prominent  place  in 
the  history  of  science. 

From  the  time  of  the  Renaissance  on  science  grew 
steadily,  but  it  was  not  till  the  latter  half  of  the  eight- 
eenth century  that  the  foundations  in  most  of  the  lines 
recognized  to-day  were  fully  laid.  Much  of  what  was 
accomplished  then  is,  at  least,  outlined  in  the  chapters 
following. 

Our  standpoint  in  the  early  years  of  the  nineteenth 
century,  just  before  the  American  Journal  had  its  begin- 
ning, may  be  briefly  summarized  as  follows:  A  desire 
for  knowledge  was  almost  universal  and,  therefore,  also 
a  general  interest  in  the  development  of  science.  Mathe- 
matics was  firmly  established  and  the  mathematical  side 
of  astronomy  and  natural  philosophy — as  physics  was 
then  called — was  well  developed.     Many  of  the  phenom- 


AMERICAN  JOURNAL  OF  SCIENCE  17 

ena  of  heat  and  their  applications,  as  in  the  steam  engine 
of  Watt,  were  known  and  even  the  true  nature  of  heat  had 
been  almost  established  by  our  countryman.  Count  Rum- 
ford  ;  but  of  electricity  there  were  only  a  few  sparks  of 
knowledge.  Chemistry  had  had  its  foundation  firmly 
laid  by  Priestley,  Lavoisier,  and  Dalton,  while  Berzelius 
was  pushing  rapidly  forward.  Geology  had  also  its 
roots  down,  chiefly  through  the  work  of  Hufcton  and 
William  Smith,  though  the  earth  was  as  yet  essentially 
an  unexplored  field.  Systematic  zoology  and  botany  had 
been  firmly  grounded  by  Buff  on,  Lamarck  and  Cuvier,  on 
the  one  hand,  and  Linnaeus  on  the  other ;  but  of  all  that  is 
embraced  under  the  biology  of  the  latter  half  of  the 
nineteenth  century  the  world  knew  nothing.  The  state- 
ments of  Silliman  in  his  Introductory  Remarks  in  the 
first  number,  quoted  in  part  on  a  following  page,  put 
the  matter  still  more  fully,  but  they  are  influenced  by  the 
enthusiasm  of  the  time  and  he  could  have  had  little  com- 
prehension of  what  was  to  be  the  record  of  the  next  one 
hundred  years. 

Now,  leaving  this  hasty  and  incomplete  retrospect  and 
coming  down  to  1918,  we  find  the  contrast  between  to-day 
and  1818  perhaps  most  strikingly  brought  out,  on  the 
material  side,  if  we  consider  the  ability  of*  man,  in  the 
early  part  of  the  nineteenth  century,  to  meet  the  demands 
upon  him  in  the  matter  of  transportation  of  himself  and 
his  property.  In  1800,  he  had  hardly  advanced  beyond 
his  ancestor  of  the  earliest  civilization ;  on  the  contrary, 
he  was  still  dependent  for  transportation  on  land  upon 
the  muscular  efforts  of  himself  and  domesticated  ani- 
mals, while  at  sea  he  had  only  the  use  of  sails  in  addition. 
The  first  application  of  the  steam  engine  with  commercial 
success  was  made  by  Fulton  when,  in  1807,  the  steamboat 
** Clermont"  made  its  famous  trip  on  the  Hudson  River. 
Since  then,  step  by  step,  transportation  has  been  made 
more  and  more  rapid,  economical  and  convenient,  both  on 
land  and  water.  This  has  come  first  through  the  per- 
fection of  the  steam  engine ;  later  through  the  agency  of 
electricity,  and  still  further  and  more  universally  by  the 
use  of  gasolene  motors.  Finally,  in  these  early  years  of 
the  twentieth  century,  what  seemed  once  a  wild  dream  of 


18  A  CENTURY  OF  SCIENCE 

the  imagination  has  been  realized,  and  man  has  gained 
the  conquest  of  the  air ;  while  the  perfection  of  the  sub- 
marine is  as  wonderful  as  its  work  can  be  deadly. 

Hardly  less  marvelous  is  the  practical  annihilation  of 
space  and  time  in  the  electric  transmission  of  human 
thought  and  speech  by  wire  and  by  ether  waves.  While, 
still  further,  the  same  electrical  current  now  gives  man 
his  artificial  illumination  and  serves  him  in  a  thousand 
ways  besides. 

But  the  limitations  of  space  have  also  been  conquered, 
during  the  same  period,  by  the  spectroscope  which  brings 
a  knowledge  of  the  material  nature  of  the  sun  and  the 
fixed  stars  and  of  their  motion  in  the  line  of  sight ;  while 
spectrum  analysis  has  revealed  the  existence  of  many 
new  elements  and  opened  up  vistas  as  to  the  nature  of 
matter. 

The  chemist  and  the  physicist,  often  working  together 
in  the  investigation  of  the  problems  lying  between  their 
two  departments,  have  accumulated  a  staggering  array 
of  new  facts  from  which  the  principles  of  IJieir  sciences 
have  been  deduced.  Many  new  elements  have  been  dis- 
covered, in  fact  nearly  all  called  for  by  the  periodic  law ; 
the  so-called  fixed  gases  have  been  liquefied,  and  now  air 
in  liquid  form  is  almost  a  plaything;  the  absolute  zero 
has  been  nearly  reached  in  the  boiling  point  of  helium; 
physical  measurements  in  great  precision  have  been  car- 
ried out  in  both  directions  for  temperatures  far  beyond 
any  scale  that  was  early  conceived  possible;  the  atom, 
once  supposed  to  be  indivisible,  has  been  shown  to  be  made 
up  of  the  much  smaller  electrons,  while  its  disintegration 
in  radium  and  its  derivatives  has  been  traced  out  and 
with  consequences  only  as  yet  partly  understood  but  cer- 
tainly having  far-reaching  consequences ;  at  one  point 
we  seem  to  be  brought  near  to  the  transmutation  of  the 
elements  which  was  so  long  the  dream  of  the  alchemist. 
Still  again  photography  has  been  discovered  and  per- 
fected and  with  the  use  of  X-rays  it  gives  a  picture  of  the 
structure  of  bodies  totally  opaque  to  the  eye ;  the  same 
X-rays  seem  likely  to  locate  and  determine  the  atoms  in 
the  crystal. 

Here  and  at  many  other  points  we  are  reaching  out  to 
a  knowledge  of  the  ultimate  nature  of  matter. 


AMERICAN  JOURNAL  OF  SCIENCE  19 

In  geology,  vast  progress  has  been  made  in  the 
knowledge  of  the  earth,  not  only  as  to  its  features  now 
exhibited  at  or  near  the  surface,  but  also  as  to  its  history 
in  past  ages,  of  the  development  of  its  structure,  the 
minute  history  of  its  life,  the  phenomena  of  its  earth- 
quakes, volcanoes,  etc.  Geological  surveys  in  all  civilized 
countries  have  been  carried  to  a  high  degree  of  per- 
fection. 

In  biology,  itself  a  word  which  though  used  by 
Lamarck  did  not  come  into  use  till  taken  up  by  Huxley, 
and  then  by  Herbert  Spencer  in  the  middle  of  the  cen- 
tury, the  progress  is  no  less  remarkable  as  is  well  devel- 
oped in  a  later  chapter  of  this  volume. 

Although  not  falling  within  our  sphere,  it  would  be 
wrong,  too,  not  to  recognize  also  the  growth  of  medicine, 
especially  through  the  knowledge  of  bacteria  and  their 
functions,  and  of  disease  germs  and  the  methods  of  com- 
bating them.  The  world  can  never  forget  the  debt  it 
owes  to  Pasteur  and  Lister  and  many  later  investigators 
in  this  field. 

To  follow  out  this  subject  further  would  be  to  encroach 
upon  the  field  of  the  chapters  following,  but,  more 
important  and  fundamental  still  than  all  the  facts  dis- 
covered and  the  phenomena  investigated  has  been  the 
establishment  of  certain  broad  scientific  principles  which 
have  revolutionized  modern  thought  and  shown  the  rela- 
tion between  sciences  seemingly  independent.  The  law 
of  conservation  of  energy  in  the  physical  world  and  the 
principle  of  material  and  organic  evolution  may  well  be 
said  to  be  the  greatest  generalizations  of  the  human 
mind.  Although  suggestions  in  regard  to  them,  particu- 
larly the  latter,  are  to  be  found  in  the  writings  of  early 
authors,  the  establishment  and  general  acceptance  of 
these  principles  belong  properly  to  the  middle  of  the 
nineteenth  century.  They  stand  as  the  crowning  achieve- 
ment of  the  scientific  thought  of  the  period  in  which  we 
are  interested. 

Any  mere  enumeration  of  the  vast  fund  of  knowledge 
accumulated  by  the  efforts  of  man  through  observation 
and  experiment  in  the  period  in  which  we  are  interested 
would  be  a  dry  summary,  and  yet  would  give  some  meas- 
ure of  what  this  marvelous  period  has  accomplished.    As 


20  A  CENTURY  OF  SCIENCE 

in  geography,  man^s  energy  has  in  recent  years  removed 
the  reproach  of  a  *^Dark  Continent, '^  of  ^* unexplored'' 
central  Asia  and  the  once  *  inaccessible  polar  regions,'' 
so  in  the  different  departments  of  science,  he  has  opened 
np  many  unknown  fields  and  accumulated  vast  stores  of 
knowledge.  It  might  even  seem  as  if  the  limit  of  the 
unknown  were  being  approached.  There  remains,  how- 
ever, this  difference  in  the  analogy,  that  in  science  the 
fundamental  relations — as,  for  example,  the  nature  of 
gravitation,  of  matter,  of  energy,  of  electricity;  the 
actual  nature  and  source  of  life — the  solution  of  these 
and  other  similar  problems  still  lies  in  the  future.  What 
the  result  of  continued  research  may  be  no  one  can  pre- 
dict, but  even  with  these  possibilities  before  us,  it  is 
hardly  rash  to  say  that  so  great  a  combined  progress  of 
pure  and  applied  science  as  that  of  the  past  hundred 
years  is  not  likely  to  be  again  realized. 

Scientific  Periodical  Literature  in  1818, 

The  contrast  in  scientific  activity  between  1818  and 
1918  is  nowhere  more  strikingly  shown  than  in  the 
amount  of  scientific  periodical  literature  of  the  two 
periods.  Of  the  thousands  of  scientific  journals  and  reg- 
ular publications  by  scientific  societies  and  academies 
to-day,  but  a  very  small  number  have  carried  on  a  con- 
tinuous and  practically  unbroken  existence  since  1818. 
This  small  amount  of  periodical  scientific  literature  in 
the  early  part  of  the  last  century  is  significant  as  giving 
a  fair  indication  of  the  very  limited  extent  to  which 
scientific  investigation  appealed  to  the  intellectual  life  of 
the  time.  Some  definite  facts  in  regard  to  the  scientific 
publications  of  those  early  days  seem  to  be  called  for. 

Learned  societies  and  academies,  devoted  to  literature 
and  science,  were  formed  very  early  but  at  first  for  occa- 
sional meetings  only  and  regular  publications  were  in 
most  cases  not  begun  till  a  very  much  later  date.  Some 
of  the  earliest — ^not  to  go  back  of  the  Renaissance — are 
the  following : 

1560.     Naples,  Academia  Secretorum  Naturae. 

1603.    Rome,  Accademia  dei  Lincei. 

1651.    Leipzig,  Academia  Naturas  Curiosum. 


AMERICAN  JOURNAL  OF  SCIENCE  21 

1657.     Florence,  Accademia  del  Cimento. 
1662.     London,  Eoyal  Society. 
1666.     Paris,  Academie  des  Sciences. 
1690.     Bologna,  Accademia  delle  Scienze. 
1700.     Berlin,    Societas   Eegia    Scientiarum.      This   was   the 
forerunner  of  the  K.  preuss.  Akad.  d.  Wissenschaften. 

The  Royal  Society  of  London,  whose  existence  dates 
from  1645,  though  not  definitely  chartered  until  1662, 
began  the  publication  of  its  **  Philosophical  Transac- 
tions'' in  1665  and  has  continued  it  practically  unbroken 
to  the  present  time ;  this  is  a  unique  record.  Following 
this,  other  early — but  in  most  cases  not  continuous — 
publications  were  those  of  Paris  (1699) ;  Berlin  (1710) ; 
Upsala  (1720);  Petrograd,  1728;  Stockholm  (1739); 
and  Copenhagen  (1743). 

For  the  latter  half  of  the  eighteenth  century,  when  the 
foundations  of  our  modern  science  were  being  rapidly 
laid,  a  considerable  list  might  be  given  of  early  publica- 
tions of  similar  scientific  bodies.  Some  of  the  prominent 
ones  are:  Gottingen  (1750),  Munich  (1759),  Brussels 
(1769),  Prague  (1775),  Turin  (1784),  Dublin  (1788),  etc. 
The  early  years  of  the  nineteenth  century  saw  the  begin- 
nings of  many  others,  particularly  in  northern  Italy.  It 
is  to  be  noted  that,  as  stated,  only  rarely  were  the  publi- 
cations of  these  learned  societies  even  approximately 
continuous.  In  the  majority  of  cases  the  issue  of  trans- 
actions or  proceedings  was  highly  irregular  and  often 
interrupted. 

In  this  country  the  earliest  scientific  bodies  are  the 
following : 

Philadelphia.  American  Philosophical  Society,  founded  in 
1743.  Transactions  were  published  1771-1809;  then  inter- 
rupted until  1818  et  seq. 

Boston.  American  Academy  of  Arts  and  Sciences,  founded 
in  1780.     Memoirs,  1785-1821 ;    and  then  1833  et  seq. 

New  Haven.  Connecticut  Academy  of  Arts  and  Sciences, 
begun  in  1799.  Memoirs,  vol.  1,  1810-16;  Transactions,  1866 
et  seq. 

Philadelphia.  Academy  of  Natural  Sciences,  begun  in  1812. 
Journal,  1817-1842 ;  and  from  1847  et  seq. 

New  York.  Lyceum  of  Natural  History,  1817;  later  (1876) 
became  the  New  York  Academy  of  Sciences.  Annals  from  1823 ; 
Proceedings  from  1870. 


22  A  CENTURY  OF  SCIENCE 

The  situation  is  somewhat  similar  as  to  independent 
scientific  journals.  A  list  of  the  names  of  those  started 
only  to  find  an  early  death  would  be  a  very  long  one,  but 
interesting  only  historically  and  as  showing  a  spasmodic 
but  unsustained  striving  after  scientific  growth. 

It  seems  worth  while,  however,  to  give  here  the  names 
of  the  periodicals  embracing  one  or  more  of  the  sub- 
jects of  the  American  Journal,  which  began  at  a  very 
early  date  and  most  of  which  have  maintained  an  unin- 
terrupted existence  down  to  1915.  It  should  be  added 
that  certain  medical  journals,  not  listed  here,  have  also 
had  a  long  and  continued  existence.^ 

Early  Scientific  Journals, 

1771-1823.  Journal  de  Physique,  Paris ;  title  changed  several 
times. 

1787-.  Botanical  Magazine.  (For  a  time  known  as  Curtis 's 
Journal.) 

1789-1816.  Annales  de  Chimie,  Paris.  Continued  from  1817 
on  as  the  Annales  de  Chimie  et  de  Physique. 

1790.  Journal  der  Physik,  Halle  (by  Gren)  ;  from  1799  on 
became  the  Annalen  der  Physik  (und  Chemie),  Halle,  Leipzig. 
The  title  has  been  somewhat  changed  from  time  to  time  though 
publication  has  been  continuous.  Often  referred  to  by  the  name 
of  the  editor-in-chief,  as  Gren,  Gilbert,  Poggendorff,  Wiedemann, 
etc. 

1795-1815.  Journal  des  Mines,  Paris,  continued  from  1816 
as  the  Annales  des  Mines. 

1796-1815.  Bibliotheque  Britannique,  Geneva.  From  1816- 
1840,  Bibliotheque  Universelle,  etc.  1846-1857,  Archives  des 
Sci.  phys.  nat.  Since  1858  generally  known  as  the  Bibliotheque 
Universelle. 

1797.  Journal  of  Natural  Philosophy,  Chemistry  and  the 
Arts  (Nicholson's  Journal)  London;  united  in  1814  with  the 
Philosophical  Magazine  (Tilloch's  Journal). 

1798-.  The  Philosophical  Magazine  (originally  by  Tilloch). 
This  absorbed  Nicholson's  Journal  (above)  in  1814;  also  the 
Annals  of  Philosophy  (Thomson,  Phillips)  in  1827  and  Brew- 
sters'  Edinburgh  Journal  of  Science  in  1832. 

1798-1803.  Allgemeines  Journal  de  Chemie  (Scherer's 
Journal).  1803-1806;  continued  as  Neues  Allg.  J.  etc.  (Geh- 
len's  Journal.)  Later  title  repeatedly  changed  and  finally 
(1834  et  seq.)  Journal  fiir  praktische  Chemie. 

1816-18.     Journal  of  Science  and  the  Arts,  London.     1819- 


AMERICAN  JOURNAL  OF  SCIENCE  23 

30,  Quarterly  J.  etc.  1830-31,  Journal  of  the  Royal  Institution 
of  Great  Britain. 

1818.  American  Journal  of  Science  and  Arts  until  1880, 
when  *'the  Arts"  was  dropped,  New  Haven,  Conn.  First 
Series,  1-50,  1818-1845 ;  Second  Series,  1-50,  1846-1870 ;  Third 
Series,  1-50,  1871-1895;    Fourth  Series,  1-45,  1896-June,  1918. 

1818.  Flora,  or  Allgemeine  botanische  Zeitung.  Regensburg, 
Munich. 

1820-1867.  London  Journal  of  Arts  and  Sciences  (after 
1855,  Newton's  Journal). 

1824—.     Annales  des  sciences  naturelles.     Paris. 

1826-.  Linnaea,  Berlin,  Halle ;  from  1882  united  with  Jahrb. 
d.  K.  botan.  Gartens. 

1828-1840.  Magazine  of  Natural  History,  London;  united 
1838  with  the  Annals  of  Natural  History,  and  known  since  1841 
as  the  Annals  and  Magazine  of  Natural  History. 

1828-.  Journal  of  the  Franklin  Institute,  Philadelphia,  from 
1826;   earlier  (1825)  the  American  Mechanics  Magazine. 

1832-.  Annalen  der  Chemie  (und  Pharmacie)  often  known 
as  Liebig's  Annalen.     Leipzig,  Lemgo. 

The  Founder  of  the  American  Journal  of  Science, 

The  establishment  of  a  scientific  journal  in  this  country 
in  1818  was  a  pioneer  undertaking,  requiring  of  its 
founder  a  rare  degree  of  energy,  courage,  and  confidence 
in  the  future.  It  was  necessary,  not  only  to  obtain  the 
material  to  fill  its  pages  and  the  money  to  carry  on  the 
enterprise,  but,  before  the  latter  end  could  be  accom- 
plished, an  audience  must  be  found  among  those  who  had 
hitherto  felt  little  or  no  interest  in  the  sciences.  This 
great  work  was  accomplished  by  Benjamin  Silliman, 
*^the  guardian  of  American  Science,''  whose  influence 
was  second  to  none  in  the  early  development  of  science  in 
this  country.  Before  speaking  in  some  detail  of  the 
early  years  of  this  Journal  and  of  its  subsequent  history, 
it  is  proper  that  some  words  should  be  given  to  its 
founder. 

Benjamin  Silliman,  son  of  a  general  prominent  in  the 
Revolutionary  War,  was  born  in  Trumbull,  Connecticut, 
on  August  8,  1779.  He  was  a  graduate  of  Yale  College 
of  the  class  of  1796.  Though  at  first  a  student  of  law  and 
accepted  for  the  bar  in  Connecticut,  he  was  called  in  1802 
by  President  Timothy  Dwight — a  man  of  rare  breadth  of 


24  A  CENTURY  OF  SCIENCE 

mind — to  occupy  the  newly-made  chair  of  chemistry,  min- 
eralogy (and  later  geology)  in  Yale  College  at  New 
Haven.  To  fit  himself  for  the  work  before  him  he 
carried  on  extensive  studies  at  home  and  in  Philadelphia 
and  spent  the  year  1805  in  travels  and  study  at  London 
and  Edinburgh,  and  also  on  the  Continent.  His  active 
duties  began  in  1806  and  from  this  time  on  he  was  in  the 
service  of  Yale  College  until  his  resignation  in  1853. 
From  the  first,  Silliman  met  with  remarkable  success  as  a 
teacher  and  public  lecturer  in  arousing  an  interest  in 
science.  His  breadth  of  knowledge,  his  enthusiasm  for 
his  chosen  subjects  and  power  of  clear  presentation,  com- 
bined with  his  fine  presence  and  attractive  personality, 
made  him  a  great  leader  in  the  science  of  the  country  and 
gave  him  a  unique  position  in  the  history  of  its  develop- 
ment. 

Much  might  be  said  of  the  man  and  his  work,  but,  the 
best  tribute  is  that  of  James  Dwight  Dana,  given  in  his 
inaugural  address  upon  the  occasion  of  his  beginning  his 
duties  as  Silliman  professor  of  geology  in  Yale  College. 
This  was  delivered  on  February  18,  1856,  in  what  was 
then  known  as  the  ** Cabinet  Building.''  Dana  says 
in  part : 

* '  In  entering  upon  the  duties  of  this  place,  my  thoughts  turn 
rather  to  the  past  than  to  the  subject  of  the  present  hour.  I 
feel  that  it  is  an  honored  place,  honored  by  the  labors  of  one 
who  has  been  the  guardian  of  American  Science  from  its  child- 
hood; who  here  first  opened  to  the  country  the  wonderful 
records  of  geology ;  whose  words  of  eloquence  and  earnest  truth 
were  but  the  overflow  of  a  soul  full  of  noble  sentiments  and 
warm  sympathies,  the  whole  throwing  a  peculiar  charm  over 
his  learning,  and  rendering  his  name  beloved  as  well  as  illus- 
trious. Just  fifty  years  since.  Professor  Silliman  took  his  sta- 
tion at  the  head  of  chemical  and  geological  science  in  this  college. 
Geology  was  then  hardly  known  by  name  in  the  land,  out  of 
these  walls.  Two  years  before,  previous  to  his  tour  in  Europe, 
the  whole  cabinet  of  Yale  was  a  half-bushel  of  unlabelled  stones. 
On  visiting  England  he  found  even  in  London  no  school  public 
or  private,  for  geological  instruction,  and  the  science  was  not 
named  in  the  English  universities.  To  the  mines,  quarries,  and 
cliffs  of  England,  the  crags  of  Scotland,  and  the  meadows  of 
Holland  he  looked  for  knowledge,  and  from  these  and  the  teach- 
ings of  Murray,  Jameson,  Hall,  Hope,  and  Playfair,  at  Edin- 
burgh, Professor  Silliman  returned,  equipped  for  duty, — albeit 


AMERICAN  JOURNAL  OF  SCIENCE  25 

a  great  duty, — that  of  laying  the  foundation,  and  creating 
almost  out  of  nothing  a  department  not  before  recognized  in  any 
institution  in  America. 

He  began  his  work  in  1806.  The  science  was  without  books — 
and,  too,  without  system,  except  such  as  its  few  cultivators  had 
each  for  himself  in  his  conceptions.  It  was  the  age  of  the  first 
beginnings  of  geology,  when  Wernerians  and  Huttonians  were 
arrayed  in  a  contest.  .  .  .  Professor  Silliman  when  at  Edin- 
burgh witnessed  the  strife,  and  while,  as  he  says,  his  earliest 
predilections  were  for  the  more  peaceful  mode  of  rock-making, 
these  soon  yielded  to  the  accumulating  evidence,  and  both  views 
became  combined  in  his  mind  in  one  harmonious  whole.  The 
science,  thus  evolved,  grew  with  him  and  by  him;  for  his  own 
labors  contributed  to  its  extension.  Every  year  was  a  year  of 
expansion  and  onward  development,  and  the  grandeur  of  the 
opening  views  found  in  him  a  ready  and  appreciative  response. 

And  while  the  sciences  and  truth  have  thus  made  progress 
here,  through  these  labors  of  fifty  years,  the  means  of  study  in 
the  institution  have  no  less  increased.  Instead  of  that  half- 
bushel  of  stones,  which  once  went  to  Philadelphia  for  names,  in 
a  candle-box,  you  see  above  the  largest  mineral  cabinet  in  the 
country,  which  but  for  Professor  Silliman,  his  attractions  and 
his  personal  exertions  together,  would  never  have  been  one  of 
the  glories  of  old  Yale.    .    .    . 

Moreover,  the  American  Journal  of  Science, — ^now  in  its 
thirty-seventh  year  and  seventieth  volume  [1856], — projected 
and  long-sustained  solely  by  Professor  Silliman,  while  ever  dis- 
tributing truth,  has  also  been  ever  gathering  honors,  and  is  one 
of  the  laurels  of  Yale. 

We  rejoice  that  in  laying  aside  his  studies,  after  so  many 
years  of  labor,  there  is  still  no  abated  vigor.  .  .  .  He  retires 
as  one  whose  right  it  is  to  throw  the  burden  on  others.  Long 
may  he  be  with  us,  to  enjoy  the  good  he  has  done,  and  cheer  us 
by  his  noble  and  benign  presence.*' 

In  addition  to  these  words  of  Dana,  mucli  of  vital 
interest  in  regard  to  Silliman  and  his  work  will  be 
gathered  from  what  is  given  in  the  pages  immediately 
following,  quoted  from  his  personal  statements  in  the 
early  volumes  of  the  Journal. 

The  Early  Years  of  the  Journal, 

In  no  direction  did  Silliman 's  enthusiastic  activities  in 
science  produce  a  more  enduring  result  than  in  the  found- 


THE 

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MORE    ESPECIALLY    OF 


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AND   THE 

^OTHER  BRANCHES  OF  NATURAL  HISTORY; 

^^^  INCLUDING   ALSO 

AND  THE 

ORNAMENTAL  AS  WELL  AS  USEFUL 

CONDUCTED   BY 

PROKKSSOR  OF  CHEMISTRY,  MINKRAI.0G7.  ETC     IN  TALK  COLtKOE,  AfTHOR  OF 
TRAVELS  1»   KNOLANn.  SCOTLAND.  AND   BOLLAND,   ETC 

— •;*,',>;3'''>- — 

VOL.  I NO.  r 

— ^v^^s^ — 

ENGRAVING    IN    THE   PRESENT    NO. 

Nevf  apl^ratus  Tor  the  combustion  of  Tar,  &.c.  by  ihc  vapoar  of 


W) 


AMERICAN  JOURNAL  OF  SCIENCE  27 

ing  and  carrying  on  of  the  Journal.  The  first  sugges- 
tion in  regard  to  the  enterprise  was  made  to  Silliman  by 
his  friend,  Colonel  George  Gibbs,  from  whom  the  famous 
Gibbs  collection  of  minerals  was  bought  by  Yale  College 
in  1825.     Silliman  says  (25,  215, 1834) : 

''Col.  Gibbs  was  the  person  who  first  suggested  to  the  Editor 
the  project  of  this  Journal,  and  he  urged  the  topic  with  so  much 
zeal  and  with  such  cogent  arguments,  as  prevailed  to  induce  the 
effort  in  a  case  then  viewed  as  of  very  dubious  success.  The 
subject  was  thus  started  in  November,  1817;  proposals  for  the 
Journal  were  issued  in  January,  1818,  and  the  first  number 
appeared  in  July  of  that  year." 

He  adds  further  (50,  p.  iii,  1847)  that  the  conversation 
here  recorded  took  place  **on  an  accidental  meeting  on 
board  the  steamboat  Fulton  in  Long  Island  Sound.'' 
This  was  some  ten  years  after  Robert  Fulton's  steam- 
boat, the  Clermont,  made  its  pioneer  trip  on  the  Hudson 
river,  already  alluded  to.  The  incident  is  not  without 
significance  in  this  connection.  The  deck  of  the  **  Ful- 
ton" was  not  an  inappropriate  place  for  the  inauguration 
of  an  enterprise  also  great  in  its  results  for  the  country. 

In  the  preface  to  the  concluding  volume  of  the  First 
Series  (loc.  cit.)  Silliman  adds  the  following  remarks 
which  show  his  natural  modesty  at  the  thought  of  under- 
taking so  serious  a  work.    He  says : 

Although  a  different  selection  of  an  editor  would  have  been 
much  preferred,  and  many  reasons,  public  and  personal,  con- 
curred to  produce  diffidence  of  success,  the  arguments  of  Col. 
Gibbs,  whose  views  on  subjects  of  science  were  entitled  to  the 
most  respectful  consideration,  and  had  justly  great  weight, 
being  pressed  with  zeal  and  ability,  induced  a  reluctant  assent; 
and  accordingly,  after  due  consultation  with  many  competent 
judges,  the  proposals  were  issued  early  in  1818,  embracing  the 
whole  range  of  physical  science  and  its  applications.  The 
Editor  in  entering  on  the  duty,  regarded  it  as  an  affair  for  life, 
and  the  thirty  years  of  experience  which  he  has  now  had,  have 
proved  that  his  views  of  the  exigencies  of  the  service  were  not 
erroneous. 

The  plan  with  which  the  editor  began  his  work  and  the 
lines  laid  down  by  him  at  the  outset  can  only  be  made 
clear  by  quoting  entire  the  *^Plan  of  the  Work"  which 


28  A  CENTIJEY  OF  SCIENCE 

opens  the  first  number.  It  seems  desirable  also  to  give 
this  in  its  original  form  as  to  paragraphs  and  typog- 
raphy. The  first  page  of  the  cover  of  the  opening  num- 
ber has  also  been  reproduced  here.  It  will  be  seen  that 
the  plan  of  the  young  editor  was  as  wide  as  the  entire 
range  of  science  and  its  applications  and  extended  out  to 
music  and  the  fine  arts.  This  seems  strange  to-day,  but 
it  must  be  remembered  how  few  were  the  organs  of  pub- 
lication open  to  contributors  at  the  time.  If  the  plan 
was  unreasonably  extended,  that  fact  is  to  be  taken  not 
only  as  an  expression  of  the  enthusiasm  of  the  editor,  as 
yet  inexperienced  in  his  work,  but  also  of  the  time  when 
the  sciences  were  still  in  their  infancy. 
He  says  (1,  pp.  v,  vi) : 

'TLAN  OF  THE  WORK. 

This  Journal  is  intended  to  embrace  the  circle  of  The  Phys- 
ical SciENOES,  with  their  application  to  The  Arts,  and  to  every 
useful  purpose. 

It  is  designed  as  a  deposit  for  original  American  communica- 
tions; but  will  contain  also  occasional  selections  from  Foreign 
Journals,  and  notices  of  the  progress  of  science  in  other  coun- 
tries.    Within  its  plan  are  embraced 

Natural  History,  in  its  three  great  departments  of  Miner- 
alogy, Botany,  and  Zoology; 

Chemistry  and  Natural  Philosophy,  in  their  various 
branches :  and  Mathematics,  pure  and  mixed. 

It  will  be  a  leading  object  to  illustrate  American  Natural 
History,  and  especially  our  Mineralogy  and  Geology. 

The  Applications  of  these  sciences  are  obviously  as  numer- 
ous as  physical  arts,  and  physical  wants;  for  no  one  of  these 
arts  or  wants  can  be  named  which  is  not  connected  with  them. 

While  Science  will  be  cherished  for  its  own  sake,  and  with  a 
due  respect  for  its  own  inherent  dignity;  it  will  also  be 
employed  as  the  handmaid  to  the  Arts.  Its  numerous  applica- 
tions to  Agriculture,  the  earliest  and  most  important  of  them ; 
to  our  Manufactures,  both  mechanical  and  chemical;  and 
to  our  Domestic  Economy,  will  be  carefully  sought  out,  and 
faithfully  made. 

It  is  also  within  the  design  of  this  Journal  to  receive  communi- 
cations on  Music,  Sculpture,  Engraving,  Painting,  and  gener- 
ally on  the  fine  and  liberal,  as  well  as  useful  arts ; 

On  Military  and  Civil  Engineering,  and  the  art  of  Navigation. 


/^Y    OT^t4^ 


/  /\f^'V6/^U^^yi^ 


o^u-^ 


^' 


AMERICAN  JOURNAL  OF  SCIENCE  29 

Notices,  Reviews,  and  Analyses  of  new  scientific  works,  and 
of  new  Inventions,  and  Specifications  of  Patents; 

Biographical  and  Obituary  Notices  of  scientific  men;  essays 
on  Comparative  Anatomy  and  Physiology,  and  generally  on 
such  other  branches  of  medicine  as  depend  on  scientific  prin- 
ciples ; 

Meteorological  Registers,  and  Reports  of  Agricultural  Experi- 
ments :  and  we  would  leave  room  also  for  interesting  miscellane- 
ous things,  not  perhaps  exactly  included  under  either  of  the 
above  heads. 

Communications  are  respectfully  solicited  from  men  of 
science,  and  from  men  versed  in  the  practical  arts. 

Learned  Societies  are  invited  to  make  this  Journal,  occasion- 
ally, the  vehicle  of  their  communications  to  the  Public. 

The  editor  will  not  hold  himself  responsible  for  the  sentiments 
and  opinions  advanced  by  his  correspondents;  but  he  will  con- 
sider it  as  an  allowed  liberty  to  make  slight  verbal  alterations, 
where  errors  may  be  presumed  to  have  arisen  from  inadver- 
tency.'' 

In  the  ** Advertisement*'  which  precedes  the  above 
statement  in  the  first  number,  the  editor  remarks  some- 
what naively  that  he  *^does  not  pledge  himself  that  all  the 
subjects  shall  be  touched  upon  in  every  number.  This  is 
plainly  impossible  unless  every  article  should  be  very 
short  and  imperfect.  .  .'' 

The  whole  subject  is  discussed  in  all  its  relations  in 
the  '* Introductory  Remarks'*  which  open  the  first  vol- 
ume. No  apology  is  needed  for  quoting  at  considerable 
length,  for  only  in  this  way  can  the  situation  be  made 
clear,  as  seen  by  the  editor  in  1818.  Further  we  gain 
here  a  picture  of  the  intellectual  life  of  the  times  and,  not 
less  interesting,  of  the  mind  and  personality  of  the  writer. 
With  a  frank  kindliness,  eminently  characteristic  of  the 
man,  as  will  be  seen,  he  takes  the  public  fully  into  his 
confidence.  In  the  remarks  made  in  subsequent  vol- 
umes,— also  extensively  quoted — the  vicissitudes  in  the 
conduct  of  the  enterprise  are  brought  out  and  when  suc- 
cess was  no  longer  doubtful,  there  is  a  tone  of  quiet 
satisfaction  which  was  also  characteristic  and  which  the 
circumstances  fully  justified. 

The  Intkoductoky  Remakks  begin  as  follows : 

The  age  in  which  we  live  is  not  less  distinguished  by  a  vigorous 
and  successful  cultivation  of  physical  science,  than  by  its  numer- 


30  A  CENTURY  OF  SCIENCE 

ous  and  important  applications  to  the  practical  arts,  and  to  the 
common  purposes  of  life. 

In  every  enlightened  country,  men  illustrious  for  talent,  worth 
and  knowledge,  are  ardently  engaged  in  enlarging  the  bound- 
aries of  natural  science;  and  the  history  of  their  labors  and 
discoveries  is  communicated  to  the  world  chiefly  through  the 
medium  of  scientific  journals.  The  utility  of  such  journals  has 
thus  become  generally  evident ;  they  are  the  heralds  of  science ; 
they  proclaim  its  toils  and  its  achievements;  they  demonstrate 
its  intimate  connection  as  well  with  the  comfort,  as  with  the 
intellectual  and  moral  improvement  of  our  species;  and  they 
often  procure  for  it  enviable  honors  and  substantial  rewards. 

Mention  is  then  made  of  the  journals  existing  in 
England  and  France  in  1818  ^Svhich  have  long  enjoyed  a 
high  and  deserved  reputation."     He  then  continues: 

From  these  sources  our  country  reaps  and  will  long  continue 
to  reap,  an  abundant  harvest  of  information:  and  if  the  light 
of  science,  as  well  as  of  day,  springs  from  the  East,  we  will  wel- 
come the  rays  of  both;  nor  should  national  pride  induce  us  to 
reject  so  rich  an  offering. 

But  can  we  do  nothing  in  return? 

In  a  general  diffusion  of  useful  information  through  the  vari- 
ous classes  of  society,  in  activity  of  intellect  and  fertility  of 
resource  and  invention,  producing  a  highly  intelligent  popula- 
tion, we  have  no  reason  to  shrink  from  a  comparison  with  any 
country.  But  the  devoted  cultivators  of  science  in  the  United 
States  are  comparatively  few:  they  are,  however,  rapidly 
increasing  in  number.  Among  them  are  persons  distinguished 
for  their  capacity  and  attainments,  and,  notwithstanding  the 
local  feelings  nourished  by  our  state  sovereignties,  and  the  rival 
claims  of  several  of  our  larger  cities,  there  is  evidently  a  predis- 
position towards  a  concentration  of  effort,  from  which  we  may 
hope  for  the  happiest  results,  with  regard  to  the  advancement 
of  both  the  science  and  reputation  of  our  country. 

Is  it  not,  therefore,  desirable  to  furnish  some  rallying  point, 
some  object  sufficiently  interesting  to  be  nurtured  by  common 
efforts,  and  thus  to  become  the  basis  of  an  enduring,  common 
interest?  To  produce  these  efforts,  and  to  excite  this  interest, 
nothing,  perhaps,  bids  fairer  than  a  Scientific  Journal. 

The  valuable  work  already  accomplished  by  various 
medical  journals  is  then  spoken  of  and  particularly  that 
of  the  first  scientific  periodical  in  the  United  States, 
Bruce 's  Mineralogical  Journal.     This,  as  Silliman  says 


AMERICAN  JOURNAL  OF  SCIENCE  31 

(1,  p.  3,  1818),  although  *^both  in  this  country  and  in 
Europe  received  in  a  very  flattering  manner,''  did  not 
survive  the  death  of  its  founder,  and  only  a  single  vol- 
ume of  270  pages  appeared  (1810-1813). 
Silliman  continues : 

No  one,  it  is  presumed,  will  doubt  that  a  journal  devoted  to 
science,  and  embracing  a  sphere  sufficiently  extensive  to  allure 
to  its  support  the  principal  scientific  men  of  our  country,  is 
greatly  needed;  if  cordially  supported,  it  will  be  successful, 
and  if  successful,  it  will  be  a  great  public  benefit. 

Even  a  failure,  in  so  good  a  cause,  (unless  it  should  arise  from 
incapacity  or  unfaithfulness,)  cannot  be  regarded  as  dishonour- 
able. It  may  prove  only  that  the  attempt  was  premature,  and 
that  our  country  is  not  yet  ripe  for  such  an  undertaking;  for 
without  the  efficient  support  of  talent,  knowledge,  and  money, 
it  cannot  long  proceed.  No  editor  can  hope  to  carry  forward 
such  a  work  without  the  active  aid  of  scientific  and  practical 
men;  but,  at  the  same  time,  the  public  have  a  right  to  expect 
that  he  will  not  be  sparing  of  his  own  labour,  and  that  his  work 
shall  be  generally  marked  by  the  impress  of  his  own  hand.  To 
this  extent  the  editor  cheerfully  acknowledges  his  obligations 
to  the  public ;  and  it  will  be  his  endeavour  faithfully  to  redeem 
his  pledge. 

Most  of  the  periodical  works  of  our  country  have  been  short- 
lived. This,  also,  may  perish  in  its  infancy;  and  if  any  degree 
of  confidence  is  cherished  that  it  will  attain  a  maturer  age,  it  is 
derived  from  the  obvious  and  intrinsic  importance  of  the  under- 
taking; from  its  being  built  upon  permanent  and  momentous 
national  interests;  from  the  evidence  of  a  decided  approbation 
of  the  design,  on  the  part  of  gentlemen  of  the  first  eminence, 
obtained  in  the  progress  of  an  extensive  correspondence;  from 
assurance  of  support,  in  the  way  of  contributions,  from  men  of 
ability  in  many  sections  of  the  union;  and  from  the  existence 
of  such  a  crisis  in  the  affairs  of  this  country  and  of  the  world, 
as  appears  peculiarly  auspicious  to  the  success  of  every  wise  and 
good  undertaking. 

An  interesting  discussion  follows  (pp.  5-8)  as  to  the 
claims  of  the  different  branches  of  science,  and  the  extent 
to  which  they  and  their  applications  had  been  already 
developed,  also  the  spheres  still  open  to  discovery. 

The  Introductory  Remarks  close,  as  follows : 

In  a  word,  the  whole  circle  of  physical  science  is  directly 
applicable  to  human  wants  and  constantly  holds  out  a  light  to 


32  A  CENTURY  OF  SCIENCE 

the  practical  arts;  it  thus  polishes  and  benefits  society  and 
everywhere  demonstrates  both  supreme  intelligence  and  harmony 
and  beneficence  of  design  in  the  Creator. 

The  science  of  mathematics,  both  pure  and  mixed,  can  never 
cease  to  be  interesting  and  important  to  man,  as  long  as  the 
relations  of  quantity  shall  exist,  as  long  as  ships  shall  traverse 
the  ocean,  as  long  as  man  shall  measure  the  surface  or  heights 
of  the  earth  on  which  he  lives,  or  calculate  the  distances  and 
examine  the  relations  of  the  planets  and  stars;  and  as  long  as 
the  iron  reign  of  war  shall  demand  the  discharge  of  projectiles, 
or  the  construction  of  complicated  defences. 

The  closing  part  of  the  paragraph  shows  the  influence 
exerted  upon  the  mind  of  the  editor  by  the  serious  wars 
of  the  years  preceding  1818,  a  subject  alluded  to  again  at 
the  close  of  this  chapter. 

In  February,  1822,  with  the  completion  of  the  fourth 
volume,  the  editor  reviews  the  situation  which,  though 
encouraging  is  by  no  means  fully  assuring.  He  says 
(preface  to  vol.  4,  dated  Feb.  15,  1822) : 

Two  years  and  a  half  have  elapsed,  since  the  publication  of 
the  first  volume  of  this  Journal,  and  one  year  and  ten  months 
since  the  Editor  assumed  the  pecuniary  responsibility.    .     .     . 

The  work  has  not,  even  yet,  reimbursed  its  expenses,  (we 
speak  not  of  editorial  or  of  business  compensation,)  we  intend, 
that  it  has  not  paid  for  the  paper,  printing  and  engraving ;  the 
proprietors  of  the  first  volume  being  in  advance,  on  those 
accounts,  and  the  Editor  on  the  same  score,  with  respect  to  the 
aggregate  expense  of  the  three  last  volumes.  This  deficit  is, 
however,  no  longer  increasing,  as  the  receipts,  at  present,  just 
about  cover  the  expense  of  the  physical  materials,  and  of  the 
manual  labour.  A  reiterated  disclosure  of  this  kind  is  not 
grateful,  and  would  scarcely  be  manly,  were  it  not  that  the 
public,  who  alone  have  the  power  to  remove  the  difficulty,  have 
a  right  to  a  frank  exposition  of  the  state  of  the  case.  As  the 
patronage  is,  however,  growing  gradually  more  extensive,  it  is 
believed  that  the  work  will  be  eventually  sustained,  although 
it  may  be  long  before  it  will  command  any  thing  but  gratuitous 
intellectual  labour.    .    .    . 

These  facts,  with  the  obvious  one, — that  its  pages  are  supplied 
with  contributions  from  all  parts  of  the  Union,  and  occasionally 
from  Europe,  evince  that  the  work  is  received  as  a  national  and 
not  as  a  local  undertaking,  and  that  the  community  consider  it 
as  having  no  sectional  character.     Encouraged  by  this  view  of 


AMERICAN  JOURNAL  OF  SCIENCE  33 

the  subject,  and  by  the  favour  of  many  distin^ished  men,  both 
at  home  and  abroad,  and  supported  by  able  contributors,  to 
whom  the  Editor  again  tenders  his  grateful  acknowledgments, 
he  will  still  persevere,  in  the  hope  of  contributing  something 
to  the  advancement  of  our  science  and  arts,  and  towards  the 
elevation  of  our  national  character. 

In  the  autumn  of  tlie  same  year,  the  editor  closes  the 
fifth  volume  with  a  more  confident  tone  (Sept.  25,  1822) : 

A  trial  of  four  years  has  decided  the  point,  that  the  American 
Public  will  support  this  Journal.  Its  pecuniary  patronage  is 
now  such,  that  although  not  a  lucrative,  it  is  no  longer  a  hazard- 
ous enterprise.  It  is  now  also  decided,  that  the  intellectual 
resources  of  the  country  are  sufficient  to  afford  an  unfailing 
supply  of  valuable  original  communications  and  that  nothing 
but  perseverance  and  effort  are  necessary  to  give  perpetuity  to 
the  undertaking. 

The  decided  and  uniform  expression  of  public  favour  which 
the  Journal  has  received  both  at  home  and  abroad,  affords  the 
Editor  such  encouragement,  that  he  cannot  hesitate  to  per- 
severe— and  he  now  renews  the  expression  of  his  thanks  to  the 
friends  and  correspondents  of  the  work,  both  in  Europe  and  the 
United  States,  requesting  at  the  same  time  a  continuance  of  their 
friendly  influence  and  efforts. 

Still  again  in  the  preface  to  the  sixth  volume  (1823)  he 
takes  the  reader  more  fully  into  his  confidence  and  shows 
that  he  regards  the  enterprise  as  no  longer  of  doubtful 
success.     He  says ; 

The  conclusion  of  a  new  volume  of  a  work,  involving  so  much 
care,  labour  and  responsibility,  as  are  necessarily  attached,  at 
the  present  day,  to  a  Journal  of  Science  and  the  Arts,  natur- 
ally produces  in  the  mind,  a  state  of  not  ungrateful  calmness, 
and  a  disposition,  partaking  of  social  feeling,  to  say  something 
to  those  who  honour  such  a  production,  by  giving  to  it  a  small 
share  of  their  money,  and  of  their  time.  The  Editor's  first 
impression  was,  that  the  sixth  volume  should  be  sent  into  the 
world  without  an  introductory  note,  but  he  yields  to  the  impulse 
already  expressed,  and  to  the  established  usages  of  respectful 
courtesy  to  the  public,  which  a  short  preface  seems  to  imply. 
He  has  now  persevered  almost  five  years,  in  an  undertaking, 
regarded  by  many  of  the  friends  whom  he  originally  consulted, 
as  hazardous,  and  to  which  not  a  few  of  them  prophetically 
alloted  only  an  ephemeral  existence.     It  has  been  his  fortune  to 


34  A  CENTURY  OF  SCIENCE 

prosecute  this  work  without,  (till  a  very  recent  period,)  returns, 
adequate  to  its  indispensable  responsibilities; — under  a  heavy 
pressure  of  professional  and  private  duty ;  with  trying  fluctua- 
tions of  health,  and  amidst  severe  and  reiterated  domestic 
afflictions.  The  world  are  usually  indulgent  to  allusions  of  this 
nature,  when  they  have  any  relation  to  the  discharge  of  public 
duty;  and  in  this  view,  it  is  with  satisfaction,  that  the  Editor 
adds,  that  he  has  now  to  look  on  formidable  difficulties,  only  in 
retrospect,  and  with  something  of  the  feeling  of  him,  who  sees 
a  powerful  and  vanquished  foe,  slowly  retiring,  and  leaving  a 
field  no  longer  contested. 

This  Journal  which,  from  the  first,  was  fully  supplied  with 
original  communications,  is  now  sustained  by  actual  payment, 
to  such  an  extent,  that  it  may  fairly  be  considered  as  an  estab- 
lished work ;  its  patronage  is  regularly  increasing,  and  we  trust 
it  will  no  longer  justify  such  remarks  as  some  of  the  following, 
from  the  pen  of  one  of  the  most  eminent  scientific  men  in 
Europe.  ' '  Nothing  surprises  me  more,  than  the  little  encourage- 
ment which  your  Journal,"  (''which  I  always  read  with  very 
great  interest,  and  of  which  I  make  great  use,")  ''experiences 
in  America — this  must  surely  arise  from  the  present  depressed 
condition  of  trade,  and  cannot  long  continue." 

Six  years  more  of  uninterrupted  editorial  work  passed 
by,  the  sixteenth  volume  was  completed,  and  the  editor 
was  now  in  a  position  to  review  the  whole  situation  up  to 
1829.  This  preface  (dated  July  1, 1829),  which  is  quoted 
nearly  in  full,  cannot  fail  to  be  found  particularly  inter- 
esting and  from  several  standpoints,  not  the  least  for  the 
insight  it  gives  into  the  writer's  mind.  It  is  also  note- 
worthy that  at  this  early  date  it  was  found  possible  to 
pay  for  original  contributions,  a  privilege  far  beyond 
the  means  of  the  editor  of  to-day. 

When  this  Journal  was  first  projected,  very  few  believed  that 
it  would  succeed. 

Among  others,  Dr.  Dorsey  wrote  to  the  editor;  "I  predict  a 
short  life  for  you,  although  I  wish,  as  the  Spaniards  say,  that 
you  may  live  a  thousand  years."  The  work  has  not  lived  a 
thousand  years,  but  as  it  has  survived  more  than  the  hundredth 
part  of  that  period,  no  reason  is  apparent  why  it  may  not  con- 
tinue to  exist.  To  the  contributors,  disinterested  and  arduous 
as  have  been  their  exertions,  the  editor's  warmest  thanks  are 
due;  and  they  are  equally  rendered  to  numerous  personal 
friends  for  their  unwavering  support:    nor  ought  those  sub- 


AMERICAN  JOURNAL  OF  SCIENCE  35 

scribers  to  be  forgotten  who,  occupied  in  the  common  pursuits 
of  life,  have  aided,  by  their  money,  in  sustaining  the  hazardous 
novelty  of  an  American  Journal  of  Science.  A  general  appro- 
bation, sufficiently  decided  to  encourage  effort,  where  there  was 
no  other  reward,  has  supported  the  editor ;  but  he  has  not  been 
inattentive  to  the  voice  of  criticism,  whether  it  has  reached  him 
in  the  tones  of  candor  and  kindness,  or  in  those  of  severity. 
We  must  not  look  to  our  friends  for  the  full  picture  of  our 
faults.     He  is  unwise  who  neglects  the  maxim — 

— fas  est  ab  hoste  doeeri, 

and  we  may  be  sure,  that  those  are  quite  in  earnest,  whose 
pleasure  it  is,  to  place  faults  in  a  strong  light  and  bold  relief; 
and  to  throw  excellencies  into  the  shadow  of  total  eclipse. 
Minds  at  once  enlightened  and  amiable,  viewing  both  in  their 
proper  proportions,  will  however  render  the  equitable  verdict; 

Non  ego  paucis  offendar  maculis, — 

It  is  not  pretended  that  this  Journal  has  been  faultless;  there 
may  be  communications  in  it  which  had  been  better  omitted,  and 
it  is  not  doubted  that  the  power  to  command  intellectual  effort, 
by  suitable  pecuniary  reward,  would  add  to  its  purity,  as  a 
record  of  science,  and  to  its  richness,  as  a  repository  of  dis- 
coveries in  the  arts. 

But  the  editor,  even  now,  offers  payment,  at  the  rate  adopted 
by  the  literary  Journals,  for  able  original  communications,  con- 
taining especially  important  facts,  investigations  and  discoveries 
in  science,  and  practical  inventions  in  the  useful  and  ornamental 
Arts. 

As  however  his  means  are  insufficient  to  pay  for  all  the  copy, 
it  is  earnestly  requested,  that  those  gentlemen,  who,  from  other 
motives,  are  still  willing  to  write  for  this  Journal,  should  con- 
tinue to  favor  it  with  their  communications.  That  the  period 
when  satisfactory  compensation  can  be  made  to  all  writers  whose 
pieces  are  inserted,  and  to  whom  payment  will  be  acceptable,  is 
not  distant,  may  perhaps  be  hoped,  from  the  spontaneous  expres- 
sion of  the  following  opinion,  by  the  distinguished  editor  of  one 
of  our  principal  literary  journals,  whose  letter  is  now  before 
me.  *'The  character  of  the  American  Journal  is  strictly 
national,  and  it  is  the  only  vehicle  of  communication  in  which 
an  inquirer  may  be  sure  to  find  what  is  most  interesting  in  the 
wide  range  of  topics,  which  its  design  embraces.  It  has  become 
in  short,  not  more  identified  with  the  science  than  the  literature 
of  the  country. '^  It  is  believed  that  a  strict  examination  of 
its  contents  will  prove  that  its  character  has  been  decidedly 
scientific ;  and  the  opinion  is  often  expressed  to  the  editor,  that 


36  A  CENTUEY  OF  SCIENCE 

in  common  with  the  journals  of  our  Academies,  it  is  a  work  of 
reference,  indispensable  to  him  who  would  examine  the  progress 
of  American  science  during  the  period  which  it  covers.  That  it 
might  not  be  too  repulsive  to  the  general  reader,  some  miscel- 
laneous pieces  have  occasionally  occupied  its  pages;  but  in 
smaller  proportion,  than  is  common  with  several  of  the  most 
distinguished  British  Journals  of  Science. 

Still,  the  editor  has  been  frequently  solicited,  both  in  public 
and  private,  to  make  it  more  miscellaneous,  that  it  might  be 
more  acceptable  to  the  intelligent  and  well  educated  man,  who 
does  not  cultivate  science;  but  he  has  never  lost  sight  of  his 
great  object,  which  was  to  produce  and  concentrate  original 
American  effort  in  science,  and  thus  he  has  foregone  pecuniary 
returns,  which  by  pursuing  the  other  course,  might  have  been 
rendered  important.  Others  would  not  have  him  admit  any 
thing  that  is  not  strictly  and  technically  scientific;  and  would 
make  this  journal  for  mere  professors  and  amateurs ;  especially 
in  regard  to  those  numerous  details  in  natural  history,  which 
although  important  to  be  registered,  (and  which,  when  pre- 
sented, have  always  been  recorded  in  the  American  Journal,) 
can  never  exclusively  occupy  the  pages  of  any  such  work  without 
repelling  the  majority  of  readers. 

If  this  is  true  even  in  Great  Britain  it  is  still  more  so  in  this 
country;  and  our  savants,  unless  they  would  be,  not  only  the 
exclusive  admirers,  but  the  sole  purchasers  of  their  own  works, 
must  permit  a  little  of  the  graceful  drapery  of  general  literature 
to  flow  around  the  cold  statues  of  science.  The  editor  of  this 
Journal,  strongly  inclined,  both  from  opinion  and  habit,  to 
gratify  the  cultivators  of  science,  will  still  do  everything  in  his 
power  to  promote  its  high  interests,  and  as  he  hopes  in  a  better 
manner  than  heretofore;  but  these  respectable  gentlemen  will 
have  the  courtesy,  to  yield  something  to  the  reading  literary,  as 
well  as  scientific  public,  and  will  not,  we  trust,  be  disgusted, 
if  now  and  then  an  Oasis  relieves  the  eye,  and  a  living  stream 
refreshes  the  traveller.  Not  being  inclined  to  renew  the  abortive 
experiment,  to  please  every  body,  which  has  been  so  long 
renowned  in  fable;  the  editor  will  endeavor  to  pursue,  the 
even  tenor  of  his  way;  altogther  inclined  to  be  courteous  and 
useful  to  his  fellow  travellers,  and  hoping  for  their  kindness 
and  services  in  return. 

The  Close  of  the  First  Series, 

The  ** First  Series,"  as  it  was  henceforth  to  be  known, 
closed  with  the  fiftieth  volume  (1847,  pp.  xx  +  347). 
This  final  volume  is  devoted  to  an  exhaustive  index  to  the 


yicUws-^  ws).  ^3-«*-^A^ 


AMERICAN  JOURNAL  OF  SCIENCE  37 

forty-nine  volumes  preceding.  In  the  preface  (dated 
April  19,  1847)  the  elder  Silliman,  now  the  senior  editor, 
reviews  the  work  that  had  been  accomplished  with  a 
frank  expression  of  his  feeling  of  satisfaction  in  the  vic- 
tory won  against  great  obstacles ;  with  this  every  reader 
must  sympathize.  He  quotes  here  at  length  (but  in 
slightly  altered  form)  the  matter  from  the  first  volume 
(1818),  which  has  been  already  reproduced  almost 
entire,  and  then  goes  on  as  follows  (pp.  xi  et  seq.) : 

Such  was  the  pledge  which,  on  entering  upon  our  editorial 
labors  in  1818,  we  gave  to  the  public,  and  such  were  the  views 
which  we  then  entertained,  regarding  science  and  the  arts  as 
connected  with  the  interests  and  honor  of  our  country  and  of 
mankind.  In  the  retrospect,  we  realize  a  sober  but  grateful 
feeling  of  satisfaction,  in  having,  to  the  extent  of  our  power, 
discharged  these  self-imposed  obligations;  this  feeling  is  chas- 
tened also  by  a  deep  sense  of  gratitude,  first  to  God  for  life  and 
power  continued  for  so  high  a  purpose ;  and  next,  to  our  noble 
band  of  contributors,  whose  labors  are  recorded  in  half  a  century 
of  volumes,  and  in  more  than  a  quarter  of  a  century  of  years. 
We  need  not  conceal  our  conviction,  that  the  views  expressed 
in  these  ''Introductory  Remarks,"  have  been  fully  sustained 
by  our  fellow  laborers. 

Should  we  appear  to  take  higher  ground  than  becomes  us, 
we  find  our  vindication  in  the  fact,  that  we  have  heralded 
chiefly  the  doings  and  the  fame  of  others.  The  work  has  indeed 
borne  throughout  ''the  impress"  of  editorial  unity  of  design, 
and  much  that  has  flowed  from  one  pen,  and  not  a  little  from 
the  pens  of  others,  has  been  without  a  name.  The  materials 
for  the  pile,  have  however  been  selected  and  brought  in,  chiefly 
by  other  hands,  and  if  the  monument  which  has  been  reared 
should  prove  to  be  ^^aere  perennius/'  the  honor  is  not  the  sole 
property  of  the  architect;  those  who  have  quarried,  hewn  and 
polished  the  granite  and  the  marble,  are  fully  entitled  to  the 
enduring  record  of  their  names  already  deeply  cut  into  the 
massy  blocks,  which  themselves  have  furnished. 

If  a  retrospective  survey  of  the  labors  of  thirty  years  on  this 
occasion  has  rekindled  a  degree  of  enthusiasm,  it  is  a  natural 
result  of  an  examination  of  all  our  volumes  from  the  contents 
of  which  we  have  endeavored  to  make  out  a  summary  both  of 
the  laborers  and  their  works.    .    .    . 

The  series  of  volumes  must  ever  form  a  work  of  permanent 
interest  on  account  of  its  exhibiting  the  progress  of  American 
science   during  the  long  period  which  it  covers.      Comparing 


38  A  CENTURY  OF  SCIENCE 

1817  with  1847,  we  mark  on  this  subject  a  very  gratifying  change. 
The  cultivators  of  science  in  the  United  States  were  then  few — 
now  they  are  numerous.  Societies  and  associations  of  various 
names,  for  the  cultivation  of  natural  history,  have  been  insti- 
tuted in  very  many  of  our  cities  and  towns,  and  several  of  them 
have  been  active  and  efficient  in  making  original  observations 
and  forming  collections. 

A  summary  follows  presenting  some  facts  as  to  the 
growth  of  scientific  societies  and  scientific  collections  in 
this  country  during  the  period  involved:  Then  the 
striking  contrast  between  1818  and  1847  in  the  matter  of 
organized  effort  toward  scientific  exploration  is  dis- 
cussed, as  follows  (pp.  xvi  et  seq.) : 

When  we  began  our  Journal,  not  one  of  the  States  had  been 
surveyed  in  relation  to  its  geology  and  natural  history;  now 
those  that  have  not  been  explored  are  few  in  number.  State 
collections  and  a  United  States  Museum  hold  forth  many  allure- 
ments to  the  young  naturalist,  as  well  as  to  the  archaeologist  and 
the  student  of  his  own  race.  The  late  Exploring  Expedition 
[Wilkes]  with  the  National  Institute,  has  enriched  the  capital 
with  treasures  rarely  equalled  in  any  country,  and  the  Smith- 
sonian Institution  recently  organized  at  Washington,  is  about 
to  begin  its  labors  for  the  increase  and  diffusion  of  knowledge 
among  men. 

It  must  not  be  forgotten  that  the  American  Association  of 
Geologists  and  Naturalists — composed  of  individuals  assembled 
from  widely  separate  portions  of  the  Union — by  the  seven  ses- 
sions which  it  has  held,  and  by  its  rich  volume  of  reports,  has 
produced  a  concentration  and  harmony  of  effort  which  promise 
happy  results,  especially  as,  like  the  British  Association,  it 
visits  different  towns  and  cities  in  its  annual  progress. 

Astronomy  now  lifts  its  exploring  tubes  from  the  observatories 
of  many  of  our  institutions.  Even  the  Ohio,  which  within  the 
memory  of  the  oldest  living  men,  rolled  along  its  dark  waters 
through  interminable  forests,  or  received  the  stains  of  blood 
from  deadly  Indian  warfare,  now  beholds  on  one  of  its  most 
beautiful  hills,  and  near  its  splendid  city,  a  permanent  obser- 
vatory with  a  noble  telescope  sweeping  the  heavens,  by  the  hand 
of  a  zealous  and  gifted  observer.  At  Washington  also,  under 
the  powerful  patronage  of  the  general  government,  an  excellent 
observatory  has  been  established,  and  is  furnished  with  superior 
instruments,  under  the  direction  of  a  vigilant  and  well  instructed 
astronomer — seconded  by  able  and  zealous  assistants. 

Here  also  (in  Yale  College)  successful  observations  have  been 


AMERICAN  JOURNAL  OF  SCIENCE  39 

made  with  good  instruments,  although  no  permanent  building 
has  been  erected  for  an  Observatory. 

We  only  give  single  examples  by  way  of  illustration,  for  the 
history  of  the  progress  of  science  in  the  United  States,  and  of 
institutions  for  its  promotion,  during  the  present  generation, 
would  demand  a  volume.  It  is  enough  for  our  purpose  that 
science  is  understood  and  valued,  and  the  right  methods  of 
prosecuting  it  are  known,  and  the  time  is  at  hand  when  its  moral 
and  intellectual  use  will  be  as  obvious  as  its  physical  applica- 
tions. Nor  is  it  to  be  forgotten  that  we  have  awakened  an 
European  interest  in  our  researches;  general  science  has  been 
illustrated  by  treasures  of  facts  drawn  from  this  country,  and 
our  discoveries  are  eagerly  sought  for  and  published  abroad. 

While  with  our  co-workers  in  many  parts  of  our  broad  land, 
v^e  rejoice  in  this  auspicious  change,  we  are  far  from  arrogating 
it  to  ourselves.  Multiplied  labors  of  many  hands  have  produced 
the  great  results.  In  the  place  which  we  have  occupied,  we 
have  persevered  despite  of  all  discouragements,  and  may,  with 
our  numerous  coadjutors,  claim  some  share  in  the  honors  of  the 
day.  We  do  not  say  that  our  work  might  not  have  been  better 
done — ^but  we  may  declare  with  truth  that  we  have  done  all  in 
our  power,  and  it  is  something  to  have  excited  many  others  to 
effort  and  to  have  chronicled  their  deeds  in  our  annals.  Let 
those  that  follow  us  labor  with  like  zeal  and  perseverance,  and 
the  good  cause  will  continue  to  advance  and  prosper.  It  is  the 
cause  of  truth — science  is  only  embodied  and  sympathized  truth 
and  in  the  beautiful  conception  of  our  noble  Agassiz — *'it  tells 
the  thought  of  God." 

The  preface  closes  with  some  personal  remarks : 

In  tracing  back  the  associations  of  many  gone-by  years,  a 
host  of  thoughts  rush  in,  and  pensive  remembrance  of  the  dead 
who  have  labored  with  us  casts  deep  shadows  into  the  vista 
through  which  we  view  the  past. 

Anticipation  of  the  hour  of  discharge,  when  our  summons 
shall  arrive,  gives  sobriety  to  thought  and  checks  the  confidence 
which  health  and  continued  power  to  act  might  naturally  inspire, 
were  we  not  reproved,  almost  every  day,  by  the  death  of  some 
co-eval,  co-worker,  companion,  friend  or  patron.  This  very  hour 
is  saddened  by  such  an  event, — but  we  will  continue  to  labor 
on,  and  strive  to  be  found  at  our  post  of  duty,  until  there  is 
nothing  more  for  us  to  do ;  trusting  our  hopes  for  a  future  life 
in  the  hands  of  Him  who  placed  us  in  the  midst  of  the  splendid 
garniture  of  this  lower  world,  and  who  has  made  not  less  ample 
provision  for  another  and  a  better. 


40  A  CENTURY  OF  SCIENCE 

Editorial  and  financial. — The  editorial  labors  on  the 
Journal  were  carried  by  the  elder  Silliman  alone  for 
twenty  years  from  1818  to  1838.  As  has  been  clearly 
shown  in  his  statements,  already  quoted,  he  was,  after  the 
first  beginning,  personally  responsible  also  for  the  finan- 
cial side  of  the  enterprise.  With  volume  34  (1838)  the 
name  of  Benjamin  Silliman,  Jr.,  is  added  as  co-editor  on 
the  title  page.  He  was  graduated  from  Yale  College  the 
year  preceding  and  at  this  date  was  only  twenty-one 
years  old.  His  aid  was  unquestionably  of  much  service 
from  the  beginning  and  increased  rapidly  with  years  and 
experience.  The  elder  Silliman  introduces  him  in  the 
preface  to  vol.  34  (1838)  and  comes  back  to  the  subject 
again  in  the  preface  to  vol.  50  (1847).  The  whole  edi- 
torial situation  is  here  presented  as  follows : 

''During  twenty  years  from  the  inception  of  this  Journal,  the 
editor  labored  alone,  although  overtures  for  editorial  co-opera- 
tion had  been  made  to  him  by  gentlemen  commanding  his  con- 
fidence and  esteem,  and  who  would  personally  have  been  very 
acceptable.  It  was,  however,  his  opinion  that  the  unity  of 
purpose  and  action  so  essential  to  the  success  of  such  a  work 
were  best  secured  by  individuality;  but  he  made  every  effort, 
and  not  without  success,  to  conciliate  the  good  will  and  to  secure 
the  assistance  of  gentlemen  eminent  in  particular  departments 
of  knowledge.  On  the  title  page  of  No.  1,  vol.  34,  published  in 
July,  1838,  a  new  name  is  introduced :  the  individual  to  whom 
it  belongs  having  been  for  several  years  more  or  less  concerned 
in  the  management  of  the  Journal,  and  from  his  education, 
position,  pursuits  and  taste,  as  well  as  from  affinity,  being  almost 
identified  with  the  editor,  he  seemed  to  be  quite  a  natural  ally, 
and  his  adoption  into  the  editorship  was  scarcely  a  violation  of 
individual  unity.  His  assistance  has  proved  to  be  very  import- 
ant:— ^his  near  relation  to  the  senior  editor  prevents  him  from 
saying  more,  while  justice  does  not  permit  him  to  say  less." 

As  is  distinctly  intimated  in  the  preceding  paragraph 
the  elder  Silliman  was  fortunate  in  obtaining  the  assist- 
ance in  his  editorial  labors  of  numerous  gentlemen  inter- 
ested in  the  enterprise.  Their  cooperation  provided 
many  of  the  scientific  notices,  book  reviews  and  the  like 
contained  in  the  Miscellany  with  which  each  number 
closed.  It  is  impossible,  at  this  date,  to  render  the  credit 
due  to  Silliman 's  helpers  or  even  to  mention  them  by 


AMERICAN  JOURNAL  OF  SCIENCE  41 

name.  Very  early  Asa  Gray  was  one  of  these  as  occa- 
sional notes  are  signed  by  his  initials.  Dr.  Levi  Ives  of 
New  Haven  was  another.  Prof.  J.  Griscom  of  Paris  also 
sent  numerous  contributions  even  as  early  as  1825  (see 
9,  154,  1825;  22,  192,  1832;  24,  342,  1833,  and  others). 

Some  statements  have  already  been  quoted  from  the 
early  volumes  as  to  the  business  part  of  Silliman's  enter- 
prise. The  subject  is  taken  up  more  fully  in  the  preface 
to  volume  50  (1847).  No  one  can  fail  to  marvel  at  the 
energy  and  optimism  required  to  push  the  Journal  for- 
ward when  conditions  must  have  been  so  difficult  and 
encouragement  so  scanty.     He  says  (pp.  iii,  iv) : 

This  Journal  first  appeared  in  July,  1818,  and  in  June,  1819, 
the  first  volume  of  four  numbers  and  448  pages  was  completed. 
This  scale  of  publication,  originally  deemed  sufficient,  was  found 
inadequate  to  receive  all  the  communications,  and  as  the  receipts 
proved  insufficient  to  sustain  the  expenses,  the  work,  having  but 
three  hundred  and  fifty  subscribers,  was,  at  the  end  of  the  year, 
abandoned  by  the  publishers. 

An  unprofitable  enterprise  not  being  attractive  to  the  trade, 
ten  months  elapsed  before  another  arrangement  could  be  carried 
into  effect,  and,  therefore,  No.  1  of  vol.  2  was  not  published  until 
April,  1820.  The  new  arrangement  was  one  of  mutual  responsi- 
bility for  the  expenses,  but  the  Editor  was  constrained  neverthe- 
less to  pledge  his  own  personal  credit  to  obtain  from  a  bank  the 
funds  necessary  to  begin  again,  and  from  this  responsibility  he 
was,  for  a  series  of  years,  seldom  released.  The  single  volume 
per  annum  being  found  insufficient  for  the  communications, 
two  volumes  a  year  were  afterward  published,  commencing  with 
the  second  volume. 

The  publishers  whose  names  appear  on  the  title  page 
of  the  four  numbers  of  the  first  volume  are  ^^  J.  Eastburn 
&  Co.,  Literary  Eooms,  Broadway,  New  York"  and  Howe 
&  Spalding,  New  Haven."  For  the  second  volume  and 
those  immediately  following  the  corresponding  state- 
ment *  Sprinted  and  published  by  S.  Converse  [New 
Haven]  for  the  Editor. " 

Silliman  adds  (p.  iv) : 

At  the  conclusion  of  vol.  10,  in  February,  1826,  the  work  was 
again  left  upon  the  hands  of  its  Editor ;  all  its  receipts  had  been 
absorbed  by  the  expenses,  and  it  became  necessary  now  to  pay 
a  heavy  sum  to  the  retiring  publisher,  as  an  equivalent  for  his 


42  A  CENTURY  OF  SCIENCE 

copies  of  previous  volumes,  as  it  was  deemed  necessary  either 
to  control  the  work  entirely  or  to  abandon  it.  The  Editor  was 
not  willing  to  think  of  the  latter,  especially  as  he  was  encouraged 
by  public  approbation,  and  was  cheered  onward  in  his  labors  by 
eminent  men  both  at  home  and  abroad,  and  he  saw  distinctly 
that  the  Journal  was  rendering  service  not  only  to  science  and 
the  arts,  but  to  the  reputation  of  his  country.  He  reflected, 
moreover,  that  in  almost  every  valuable  enterprise  perseverance 
in  effort  is  necessary  to  success.  He  being  now  sole  proprietor, 
a  new  arrangement  was  made  for  a  single  year,  the  publishers 
being  at  liberty,  at  the  end  of  that  time,  to  retire,  and  the  Editor 
to  resume  the  Journal  should  he  prefer  that  course. 

The  latter  alternative  he  adopted,  taking  upon  himself  the 
entire  concern,  including  both  the  business  and  the  editorial 
duties,  and  of  course,  all  the  correspondence  and  accounts. 
From  that  time  the  work  has  proceeded  without  interruption, 
two  volumes  per  annum  having  been  published  for  the  last 
twenty  years;  and  its  pecuniary  claims  ceased  to  be  onerous, 
although  its  means  have  never  been  large.    .    .    . 

Later  in  the  same  preface  lie  adds  (p.  xiv) : 

It  may  be  interesting  to  our  readers  to  know  something  of  the 
patronage  of  the  Journal.  It  has  never  reached  one  thousand 
paying  subscribers,  and  has  rarely  exceeded  seven  or  eight 
hundred — for  many  years  it  fluctuated  between  six  and  seven 
hundred. 

It  has  been  far  from  paying  a  reasonable  editorial  compensa- 
tion; often  it  has  paid  nothing,  and  at  present  it  does  little 
more  than  pay  its  bills.  The  number  of  engravings  and  the 
extra  labor  in  printer's  composition,  cause  it  to  be  an  expensive 
work,  while  its  patronage  is  limited. 

It  is  difficult  at  this  date  to  give  any  adequate  state- 
ment of  the  amount  of  encouragement  and  active  assist- 
ance given  to  Silliman  by  his  scientific  colleagues  in  New 
Haven  and  elsewhere — a  subject  earlier  alluded  to.  It 
is  fortunately  possible,  however,  to  acknowledge  the  gen- 
erous aid  received  by  the  Journal  in  the  early  days  from 
a  source  near  at  hand.  It  has  already  been  noted  in 
another  place  that  the  dawning  activity  of  science  at  New 
Haven  was  recognized  by  the  founding  of  the  '  ^  Connecti- 
cut Academy  of  Arts  and  Sciences,''  formally  estab- 
lished at  New  Haven  in  1799  and  the  third  scientific  body 
to  be  organized  in  this  country.     From  the  beginning  of 


AMERICAN  JOURNAL  OF  SCIENCE  43 

the  Journal  in  1818,  the  Connecticut  Academy  freely 
gave  its  support  both  in  papers  for  publication  and  at 
least  on  one  occasion  later  it  gave  important  financial  aid. 
Upon  the  occasion  of  the  celebration  of  the  centennial 
anniversary  of  the  Academy  on  October  11,  1899,  Pro- 
fessor, later  Governor,  Baldwin,  the  president  of  the 
Academy,  discusses  this  subject  in  some  detail.  He  says 
in  part : 

To  support  his  [Silliman's]  undertaking,  a  vote  had  been 
passed  in  February  [1818],  ''that  the  Committee  of  Publication 
may  allow  such  of  the  Academy's  papers  as  they  think  proper, 
to  be  published  in  Mr.  Silliman's  Scientific  Journal." 

Free  use  was  made  of  this  authority,  and  a  large  part  of  the 
contents  of  the  Journal  was  for  many  years  drawn  from  this 
source.  In  some  cases  this  fact  was  noted  in  publication  j^  but 
in  most  it  was  not.    .    .    . 

In  1826,  when  the  Journal  was  in  great  need  of  financial  sup- 
port, the  Academy  further  voted  to  pay  for  a  year  the  cost  of 
printing  such  of  its  papers  as  might  be  published  in  it.  In 
Baldwin's  Annals  of  Yale  College,  published  in  1831,  it  is 
described  as  a  publication  ''honorable  to  the  science  of  our 
common  country,"  and  having  "an  additional  value  as  being 
adopted  as  the  acknowledged  organ  of  the  Connecticut  Academy 
of  Arts  and  Sciences." 

Many  active  campaigns  were  carried  on  over  the 
country  through  paid  agents  to  obtain  new  subscribers 
for  the  Journal  and  it  was  doubtless  due  to  these  efforts 
that  the  nominal  subscription  list  was,  at  times,  as 
already  noted,  relatively  large  as  compared  with  that  of  a 
later  date.  The  new  subscribers  in  many  cases,  however, 
did  not  remain  permanently  interested,  often  failed  to 
pay  their  bills,  and  the  uncertain  and  varying  demand 
upon  the  supply  of  printed  copies  was  doubtless  one 
reason  why  many  single  numbers  became  early  out  of 
print. 

An  interesting  sidelight  is  thrown  upon  the  efforts  of 
Silliman  to  interest  the  public  in  his  work,  at  its  begin- 
ning, by  a  letter  to  the  editor  from  Thomas  Jefferson, 
then  seventy-five  years  of  age.  The  writer  is  indebted  to 
Mr.  Robert  B.  Adam  of  Buffalo  for  a  copy  of  this  letter 
and  its  interest  justifies  its  being  reproduced  here  entire. 
The  letter  is  as  follows : 


44  A  CENTURY  OF  SCIENCE 

Monticello,  Apr.  11.  '18. 
Sir 

Tlie  -unlucky  displacement  of  your  letter  of  Mar  3  has  been 
the  cause  of  delay  in  my  answer,  altho'  I  have  very  generally 
withdrawn  from  subscribing  to  or  reading  periodical  publica- 
tions from  the  love  of  rest  which  age  produces,  yet  I  willingly 
subscribe  to  the  journal  you  propose  from  a  confidence  that  the 
talent  with  which  it  will  be  edited  will  entitle  it  to  attention 
among  the  things  of  select  reading  for  which  alone  I  have  time 
now  left,  be  so  good  as  to  send  it  by  mail,  and  the  receipt  of 
the  1st  number  will  be  considered  as  announcing  that  the  work 
is  commenced  and  the  subscription  money  for  a  year  shall  be 
forwarded.  Accept  the  assurance  of  my  great  esteem  and 
respect. 

Th.  Jefferson 

Professor  Silliman. 

Contributors, — An  interesting  summary  is  also  given 
by  Silliman  of  the  contributors  to  the  Journal  and  the 
extent  of  their  work  (vol.  50,  pp.  xii,  xiii) ;  he  says : 

We  find  that  there  have  been  about  600  contributors  of  orig- 
inal matter  to  the  Journal,  and  we  have  the  unexpected  satis- 
faction of  believing  that  probably  five-sixths  of  them  are  still 
living;  for  we  are  not  certain  that  more  than  fifty  are  among 
the  dead;  of  perhaps  fifty  more  we  are  without  information, 
and  if  that  additional  number  is  to  be  enrolled  among  the  ' '  stel- 
ligeri,"  we  have  still  500  remaining.  Among  them  are  not  a 
few  of  the  veterans  with  whom  we  began  our  career,  and  several 
of  these  are  still  active  contributors.  Shall  we  then  conclude 
that  the  peaceful  pursuits  of  knowledge  are  favorable  to  long 
life?  This  we  think  is,  coeteris  paribus,  certainly  true:  but  in 
the  present  instance,  another  reason  can  be  assigned  for  the 
large  amount  of  survivorship.  As  the  Journal  has  advanced 
and  death  has  removed  its  scientific  contributors,  younger  men 
and  men  still  younger,  have  recruited  the  ranks,  and  volunteers 
have  enlisted  in  numbers  constantly  increasing,  so  that  the 
flower  of  the  host  are  now  in  the  morning  and  meridian  of  life. 

"We  have  been  constantly  advancing,  like  a  traveller  from  the 
equinoctial  towards  the  colder  zones, — as  we  have  increased  our 
latitude,  stars  have  set  and  new  stars  have  risen,  while  a  few 
planetary  orbs  visible  in  every  zone,  have  continued  to  cheer  us 
on  our  course. 

The  number  of  articles,  almost  exclusively  original,  contained 
in  the  Journal  is  about  1800,  and  the  Index  will  show  how  many 


AMERICAN  JOURNAL  OF  SCIENCE  45 

have  been  contributed  by  each  individual;  we  have  doubtless 
included  in  this  number  some  few  articles  republished  from 
foreign  Journals — but  we  think  they  are  even  more  than  coun- 
terbalanced by  original  communications  without  a  name  and  by 
editorial  articles,  both  of  which  have  been  generally  omitted  in 
the  enumeration. 

Of  smaller  articles  and  notices  in  the  Miscellany,  we  have  not 
made  any  enumeration,  but  they  evidently  are  more  numerous 
than  the  regular  articles,  and  we  presume  that  they  may  amount 
to  at  least  2500. 

Of  party,  either  in  politics  or  religion,  there  is  no  trace  in 
our  work;  of  personalities  there  are  none,  except  those  that 
relate  to  priority  of  claims  or  other  rights  of  individuals.  Of 
these  vindications  the  number  is  not  great,  and  we  could  heartily 
have  wished  that  there  had  been  no  occasion  for  any. 

General  Scope  of  Articles. — Many  references  will  be 
found  in  the  chapters  following  which  throw  light  upon 
the  character  and  scope  of  the  papers  published  in  the 
Journal,  particularly  in  its  early  years ;  a  few  additional 
statements  here  may,  however,  prove  of  interest. 

One  feature  that  is  especially  noticeable  is  the  frequent 
publication  of  articles  planned  to  place  before  the  read- 
ers of  the  Journal  in  full  detail  subjects  to  which  they 
might  not  otherwise  have  access.  These  are  sometimes 
translations;  sometimes  republications  of  articles  that 
had  already  appeared  in  English  periodicals;  again, 
they  are  exhaustive  and  critical  reviews  of  important 
memoirs  or  books.  The  value  of  this  feature  in  the  early 
history  of  the  Journal,  when  the  distribution  of  scientific 
literature  had  nothing  of  the  thoroughness  characteristic 
of  recent  years,  is  sufficiently  obvious. 

It  is  also  interesting  to  note  the  long  articles  of  geo- 
logical description  and  others  giving  lists  of  mineral  or 
botanical  localities.  Noteworthy,  too,  is  the  attempt  to 
keep  abreast  of  occurring  phenomena  as  in  the  many 
notes  on  tornadoes  and  storms  by  Redfield,  Loomis,  etc. ; 
on  auroras  at  different  localities ;  on  shooting  stars  by 
Herrick,  Olmstead  and  others. 

The  wide  range  of  topics  treated  of  is  quite  in  accord- 
ance with  the  plan  of  the  editor  as  given  on  an  earlier 
page.  Some  notes,  taken  more  or  less  at  random,  may 
serve  to  illustrate  this  point.    An  extended  and  quite 


46  A  CENTUEY  OF  SCIENCE 

technical  discussion  of  ^^ Musical  Temperament''  opens 
the  first  number  (1,  pp.  9-35)  and  is  concluded  in  the  same 
volume  (pp.  176-199).  An  article  on  ^^ Mystery''  is  given 
by  Mark  Hopkins,  A.M.,  "late  a  tutor  of  Williams  Col- 
lege" (13,  217,  1828).  There  is  an  essay  on  "Gypsies" 
by  J.  Griscom  (from  the  Revue  Encyclopedique)  in  vol- 
ume 24  (pp.  342-345,  1833),  while  some  notes  on  American 
gypsies  are  added  in  vol.  26  (p.  189,  1834).  The  "divin- 
ing rod"  is  described  at  length  in  vol.  11  (pp.  201-212, 
1826),  but  without  giving  any  comfort  to  the  credulous; 
on  the  contrary  the  last  paragraph  states  that  ' '  the  pre- 
tensions of  diviners  are  worthless,  etc."  A  long  article 
by  J.  Finch  on  the  forts  of  Boston  harbour  appeared 
in  1824  (8,  338-348) ;  the  concluding  paragraph  seems 
worthy  of  quotation : 

"Many  centuries  hence,  if  despotism  without,  or  anarchy 
within,  should  cause  the  republican  institutions  of  America  to 
fade,  then  these  fortresses  ought  to  he  destroyed,  because  they 
would  be  a  constant  reproach  to  the  people;  but  until  that 
period,  they  should  be  preserved  as  the  noblest  monuments  of 
liberty.'' 

The  promise  to  include  the  fine  arts  is  kept  by  the  pub- 
lication of  various  papers,  as  of  the  Trumbull  paintings 
(16,  163, 1829) ;  also  by  a  series  of  articles  on  "architec- 
ture in  the  United  States"  (17,  99,  1830;  18,  218,  220, 
1830)  and  others.  Quite  in  another  line  is  the  paper  by 
J.  W.  Gibbs  (33,  324,  1838)  on  "Arabic  words  in 
English. ' '  A  number  of  related  linguistic  papers  by  the 
same  author  are  to  be  found  in  other  volumes.  Papers 
in  pure  mathematics  are  also  not  infrequent,  though 
now  not  considered  as  falling  within  the  field  of  the 
Journal. 

Applied  science  takes  a  prominent  place  through  all  the 
volume  of  the  First  Series.  An  interesting  paper  is  that 
on  Eli  Whitney,  containing  an  account  of  the  cotton  gin ; 
this  is  accompanied  by  an  excellent  portrait  (21,  201-264, 
1832).  The  steam  engine  and  its  application  are  repeat- 
edly discussed  and  in  the  early  volumes  brief  accounts 
are  given  of  the  early  steamboats  in  use ;  for  example, 
between  Stockholm  and  St.  Petersburg  (2,  347,  1820) ; 
Trieste  and  Venice  (4,  377,  1822) ;   on  the  Swiss  Lakes 


AMERICAN  JOURNAL  OF  SCIENCE  47 

(6,  385,  1823).  The  voyage  of  the  first  Atlantic  steam- 
boat, the  ^  ^  Savannah, ' '  which  crossed  from  Savannah 
to  Liverpool  in  1819,  is  described  (38,  155,  1840) ;  men- 
tion is  also  made  of  the  ^^ first  iron  boat''  (3,  371,  1821; 
5,  396,  1822).  A  number  of  interesting  letters  on 
''Steam  Navigation"  are  given  in  vol.  35,  160,  162,  332, 
333,  336;  some  of  the  suggestions  seem  very  quaint, 
viewed  in  the  light  of  the  experience  of  to-day. 

A  very  early  form  of  explosive  engine  is  described  at 
•length  by  Samuel  Morey  (11, 104, 1826) ;  this  is  an  article 
that  deserves  mention  in  these  days  of  gasolene  motors. 
Even  more  interesting  is  the  description  by  Charles  Gris- 
wold  (2,  94,  1820)  of  the  first  submarine  invented  by 
David  Bushnell  and  used  in  the  Revolutionary  War  in 
August,  1776.  An  account  is  also  given  of  a  dirigible 
balloon  that  mav  be  fairly  regarded  as  the  original  ances- 
tor of  the  Zeppelin  (see  11,  346,  1826).  The  whole  sub- 
ject of  aerial  navigation  is  treated  at  length  by  H.  Strait 
(25,  pp.  25,  26, 1834)  and  the  expression  of  his  hopes  for 
the  future  deserve  quotation : 

''Conveyance  by  air  can  be  easily  rendered  as  safe  as  by 
water  or  land,  and  more  cheap  and  speedy,  while  the  universal 
and  uniform  diffusion  of  the  air  over  every  portion  of  the 
earth,  will  render  aerial  navigation  preferable  to  any  other.  To 
carry  it  into  effect,  there  needs  only  an  immediate  appeal  on  a 
sufficiently  large  scale,  to  experiment ;  reason  has  done  her  part, 
when  experiment  does  hers,  nature  will  not  refuse  to  sanction  the 
whole.  Aerial  navigation  will  present  the  works  of  nature  in 
all  their  charms;  to  commerce  and  the  diffusion  of  knowledge, 
it  will  bring  the  most  efficient  aid,  and  it  can  thus  be  rendered 
serviceable  to  the  whole  human  family.'' 

A  subject  of  quite  another  character  is  the  first  discus- 
sion of  the  properties  of  chloroform  (chloric  ether)  and 
its  use  as  an  anaesthetic  (Guthrie,  21,  64,  405,  1832; 
22,  105,  1832;  Levi  Ives,  21,  406).  Further  interesting 
communications  are  given  of  the  first  analyses  of  the  gas- 
tric juice  and  the  part  played  by  it  in  the  process  of 
digestion.  Dr.  William  Beaumont  of  St.  Louis  took 
advantage  of  a  patient  who  through  a  gun-shot  wound 
was  left  with  a  permanent  opening  into  his  stomach 
through  which  the  gastric  juice  could  be  drawn  off.     The 


48  A  CENTURY  OF  SCIENCE 

results  of  Dr.  Beaumont  and  of  Professor  Robley  Dungli- 
son,  to  whom  samples  were  submitted,  are  given  in  full 
in  the  life  of  Beaumont  by  Jesse  S.  Myer  (St.  Louis, 
1912).  The  interest  of  the  matter,  so  far  as  the  Journal 
is  concerned,  is  chiefly  because  Dr.  Beaumont  selected 
Professor  Silliman  as  a  chemist  to  whom  samples  for 
examination  were  also  submitted.  An  account  of  Silli- 
man's  results  is  given  in  the  Beaumont  volume  referred 
to  (see  also  26,  193,  1834).  Desiring  the  support  of  a 
chemist  of  wider  experience  in  organic  analysis,  he  also 
sent  a  sample  through  the  Swedish  consul  to  Berzelius  in 
Stockholm.  After  some  months  the  sample  was  received 
and  it  is  interesting  to  note  in  a  perfectly  fresh  condi- 
tion; it  is  to  be  regretted,  however,  that  the  Swedish 
chemist  failed  to  add  anything  to  the  results  already 
obtained  in  this  country  (27,  40b,  1835). 

The  above  list,  which  might  be  greatly  extended,  seems 
to  leave  little  ground  for  the  implied  criticism  replied  to 
by  Silliman  as  follows  (16,  p.  v,  1829) : 

A  celebrated  scholar,  while  himself  an  editor,  advised  me,  in 
a  letter,  to  introduce  into  this  Journal  as  much  ^^ readable'* 
matter  as  possible:  and  there  was,  pretty  early,  an  earnest  but 
respectful  recommendation  in  a  Philadelphia  paper,  that  Litera- 
ture, in  imitation  of  the  London  Quarterly  Journal  of  Science, 
&c.  should  be  in  form,  inscribed  among  the  titles  of  the  work. 

The  Second,  Third  and  Fourth  Series, 

The  Second  Seeies  of  the  Journal,  as  already  stated, 
began  with  January,  1846.  Up  to  this  time  the  publica- 
tion had  been  a  quarterly  or  two  volumes  annually  of  two 
numbers  each.  From  1846  until  the  completion  of  an 
additional  fifty  volumes  in  1871,  the  Journal  was  made  a 
bimonthly,  each  of  the  two  yearly  volumes  having  three 
numbers  each.  Furthermore,  a  general  index  was  given 
for  each  period  of  ^yq  years,  that  is  for  every  ten 
volumes. 

Much  more  important  than  this  change  was  the  addi- 
tion to  the  editorial  staff  of  James  Dwight  Dana,  Silli- 
man's  son-in-law.  Dana  returned  from  the  four-years 
cruise  of  the  Wilkes  Exploring  Expedition  in  1842;  he 
settled  in  New  Haven,  was  married  in  1844,  and  in  1850 


(^^^^..^.w^^ 


^xt.C.^W' 


AMEEICAN  JOUENAL  OF  SCIENCE  49 

was  appointed  Silliman  professor  of  Geology  in  Yale 
College.  He  was  at  this  time  actively  engaged  in  writ- 
ing his  three  quarto  reports  for  the  Expedition  and 
hence  did  not  begin  his  active  professional  duties  in  Yale 
College  until  1856.  Part  of  his  inaugural  address  was 
quoted  on  an  earlier  page. 

Dana  had  already  performed  the  severe  labor  of  pre- 
paring the  complete  index  to  the  First  Series,  a  volume 
of  about  350  pages,  finally  issued  in  1847.  From  the 
beginning  of  the  Second  Series  he  was  closely  associated 
with  his  brother-in-law,  the  younger  Silliman.  Later  the 
editorial  labor  devolved  more  and  more  upon  him  and  the 
larger  part  of  this  he  carried  until  about  1890.  His  work, 
was,  however,  somewhat  interrupted  during  periods  of  ill 
health.  This  was  conspicuously  true  during  a  year's 
absence  in  Europe  in  1859-60,  made  necessary  in  the 
search  for  health;  during  these  periods  the  editorial 
responsibility  rested  entirely  upon  the  younger  Silliman. 
Of  Dana's  contributions  to  science  in  general  this  is  not 
the  place  to  speak,  nor  is  the  present  writer  the  one  to 
dwell  in  detail  upon  his  work  for  the  Journal.  This  sub- 
ject is  to  such  an  extent  involved  in  the  history  of  geology 
and  zoology,  the  subjects  of  several  succeeding  chapters, 
that  it  is  adequately  presented  in  them. 

It  may,  however,  be  worth  stating  that  in  the  bibliog- 
raphy accompanying  the  obituary  notice  of  Dana  (49, 
329-356,  1895)  some  250  titles  of  articles  in  the  Journal 
are  enumerated;  these  aggregate  approximately  2800 
pages.  The  number  of  critical  notes,  abstracts,  book 
reviews,  etc.,  could  be  also  given,  were  it  worth  while,  but 
what  is  much  more  significant  in  this  connection,  than 
their  number  or  aggregate  length,  is  the  fact  that  these 
notices  are  in  a  large  number  of  cases — ^like  those  of  Gray 
in  botany — minutely  critical  and  original  in  matter. 
They  thus  give  the  writer's  own  opinion  on  a  multitude 
of  different  subjects.  It  was  a  great  benefit  to  Dana,  as 
it  was  to  science  also,  that  he  had  this  prompt  means^  at 
hand  of  putting  before  the  public  the  results  of  his  active 
brain,  which  continued  to  work  unceasingly  even  in  times 
of  health  prostration. 

This  may  be  the  most  convenient  place  to  add  that  as 
Dana  became  gradually  less  able  to  carry  the  burden  of 


50  A  CENTURY  OF  SCIENCE 

the  details  involved  in  editing  the  Journal  in  addition  to 
his  more  important  scientific  labors,  particularly  from 
1890  on,  this  work  devolved  more' and  more  upon  his  son, 
the  present  editor,  whose  name  was  added  to  the  editorial 
staff  in  1875,  with  volume  9,  of  the  Third  Series.  The 
latter  has  served  continuously  until  the  present  time, 
with  the  exception  of  absences,  due  to  ill  health,  in  1893-94 
and  in  1903 ;  during  the  first  of  these  Professor  Henry  S. 
Williams  and  during  the  second  Professor  H.  E.  Greg- 
ory occupied  the  editorial  chair. 

The  Thied  Sekies  began  in  1871,  after  the  completion 
of  the  one-hundredth  volume  from  the  beginning  in  1818. 
At  this  date  the  Journal  was  made  a  monthly  and  as  such 
it  remains  to-day.  Fifty  volumes  again  completed  this 
series,  which  closed  in  1895. 

The  FouKTH  Sekies  began  with  January,  1896,  and  the 
present  number  for  July,  1918,  is  the  opening  one  of  the 
forty-sixth  volume  or,  in  other  words, — the  one  hundred 
and  ninety-sixth  volume  of  the  entire  issue  since  1818. 
The  Fourth  Series,  according  to  the  precedent  estab- 
lished, will  end  with  1920. 

Associate  Editors. — In  1851  the  new  policy  was  intro- 
duced of  adding  ** Associate  Editors"  to  the  staff.  The 
first  of  these  was  Dr.  Wolcott  Gibbs  of  Cambridge.  He 
began  his  duties  with  the  eleventh  volume  of  the  Second 
Series  in  1851  and  continued  them  with  unceasing  care 
and  thoroughness  for  more  than  twenty  years.  In  a  note 
dated  Jan.  1,  1851  (11,  105),  he  says: 

It  is  my  intention  in  future  to  prepare  for  the  columns  of  this 
Journal  abstracts  of  the  more  important  physical  and  chemical 
memoirs  contained  in  foreign  scientific  journals,  accompanied 
by  references,  and  by  such  critical  observations  as  the  occasion 
may  demand.  Contributions  of  a  similar  character  from  others 
will  of  course  not  be  excluded  by  this  arrangement,  but  I  shall 
hold  myself  responsible  only  for  those  notices  which  appear 
over  my  initials. 

The  departments  covered  by  Dr.  Gibbs,  in  his  excellent 
monthly  contributions,  embraced  chemistry  and  physics, 
and  these  subjects  were  carried  together  until  1873  when 
they  were  separated  and  the  physical  notes  were  fur- 


AMERICAN  JOURNAL  OF  SCIENCE  51 

nished,  first  by  Alfred  M.  Mayer  and  later  successively 
by  E.  C.  Pickering  (from  1874),  J.  P.  Cooke  (from  1877), 
and  John  Trowbridge  (from  1880).  The  first  instalment 
of  the  long  series  of  notes  in  chemistry  and  chemical 
physics  by  George  F.  Barker  was  printed  in  volume  50, 
1870.  He  came  in  at  first  to  occasionally  relieve  Dr. 
Gibbs,  but  soon  took  the  entire  responsibility.  His  name 
was  placed  among  the  associate  editors  on  the  cover  in 
1877  and  two  years  later  Dr.  Gibbs  formally  retired.  It 
may  be  added  that  from  the  beginning  in  1851  to  the 
present  time,  the  notes  in  ' '  Chemistry  and  Physics  * '  have 
been  continued  almost  without  interruption. 

The  other  departments  of  science  have  been  also  fully 
represented  in  the  notes,  abstracts  of  papers  pub- 
lished, book  notices,  etc.,  of  the  successive  numbers,  but 
as  with  the  chemistry  and  physics  the  subject  of  botany 
was  long  treated  in  a  similar  formal  manner.  For  the 
notes  in  this  department,  the  Journal  was  for  many  years 
indebted  to  Dr.  Asa  Gray,  who  became  associate  editor  in 
1853,  two  years  after  Gibbs,  although  he  had  been  a 
not  infrequent  contributor  for  many  years  previously. 
Gray's  contributions  were  furnished  with  great  regu- 
larity and  were  always  critical  and  original  in  matter. 
They  formed  indeed  one  of  the  most  valuable  features 
of  the  Journal  for  many  years ;  as  botanists  well  appre- 
ciate, and,  as  Professor  Goodale  has  emphasized  in  his 
chapter  on  botany,  Gray's  notes  are  of  vital  importance 
in  the  history  of  the  development  of  his  subject.  With 
Gray's  retirement  from  active  duty,  his  colleague, 
George  W.  Goodale,  took  up  the  work  in  1888  and  in  1895 
William  G.  Farlow,  also  of  Cambridge,  was  added  as  an 
associate  editor  in  cryptogamic  botany.  At  this  time, 
however,  and  indeed  earlier,  the  sphere  of  the  Journal 
had  unavoidably  contracted  and  botany  perforce  ceased 
to  occupy  the  prominent  place  it  had  long  done  in  the 
Journal  pages. 

This  is  not  the  place  to  present  an  appreciation  of  the 
truly  magnificent  work  of  Asa  Gray.  It  may  not  be  out 
of  place,  however,  to  call  attention  to  the  notice  of  Gray 
written  for  the  Journal  by  his  life-long  friend,  James  D. 
Dana  (35,  181,  1888).  The  opening  paragraph  is  as 
follows : 


52  A  CENTURY  OF  SCIENCE 

''Our  friend  and  associate,  Asa  Gray,  the  eminent  botanist 
of  America,  the  broad-minded  student  of  nature,  ended  his  life 
of  unceasing  and  fruitful  work  on  the  30th  of  January  last. 
For  thirty-five  years  he  has  been  one  of  the  editors  of  this  Jour- 
nal, and  for  more  than  fifty  years  one  of  its  contributors ;  and 
through  all  his  communications  there  is  seen  the  profound  and 
always  delighted  student,  the  accomplished  writer,  the  just  and 
genial  critic,  and  as  Darwin  has  well  said,  '  The  lovable  man. '  ' ' 

The  third  associate  editor,  following  Gray,  was  Louis 
Agassiz,  whose  work  for  science,  particularly  in  his 
adopted  home  in  this  country,  calls  for  no  praise  here. 
His  term  of  service  extended  from  1853  to  1866  and,  par- 
ticularly in  the  earlier  years,  his  contributions  were  nu- 
merous and  important.  The  next  gentleman  in  the  list 
was  Waldo  I.  Burnett,  of  Boston,  who  served  one  year 
only,  and  then  followed  four  of  Dana's  colleagues  in  New 
Haven,  of  whose  generosity  and  able  assistance  it  would 
be  impossible  to  say  too  much.  These  gentlemen  were 
Brush  in  mineralogy ;  Johnson  in  chemistry,  particularly 
on  the  agricultural  side;  Newton  in  mathematics  and 
astronomy,  whose  contributions  will  be  spoken  of  else- 
where;   and  Verrill — a  student  of  Agassiz — in  zoology. 

All  of  these  gentlemen,  besides  their  frequent  and 
important  original  articles,  were  ever  ready  not  only  to 
give  needed  advice,  but  also,  to  furnish  brief  communi- 
cations, abstracts  of  papers  and  book  reviews,  and  other- 
wise to  aid  in  the  work.  Verrill  particularly  furnished 
the  Journal  a  long  list  of  original  and  important  papers, 
chiefly  in  systematic  zoology,  extending  from  1865 
almost  down  to  the  present  year.  His  abstracts  and 
book  notices  also  were  numerous  and  trenchant  and  it  is 
not  too  much  to  say  that  without  him  the  Journal  never 
could  have  filled  the  place  in  zoology  which  it  so  long 
held.  Much  later  the  list  of  New  Haven  men  was 
increased  by  the  addition  of  Henry  S.  Williams  (1894), 
and  0.  C.  Marsh  (1895). 

Of  the  valuable  work  of  those  more  or  less  closely  asso- 
ciated in  the  conduct  of  the  Journal  at  the  present  time, 
it  would  not  be  appropriate  to  speak  in  detail.  It  must 
suffice  to  say  that  the  services  rendered  freely  by  them 
have  been  invaluable,  and  to  their  aid  is  due  a  large  part 
of  the  success  of  the  Journal,  especially  since  the  Fourth 


Mx^^utt^joj. 


AMERICAN  JOURNAL  OF  SCIENCE  53 

Series  began  in  1896.  But  even  this  statement  is  inade- 
quate, for  the  editor-in-chief  has  had  the  generous  assist- 
ance of  other  gentlemen,  whose  names  have  not  been 
jDlaced  on  the  title  page,  and  who  have  also  played  an 
important  part  in  the  conduct  of  the  Journal.  This 
policy,  indeed,  is  not  a  matter  of  recent  date.  Very 
early  in  the  First  Series,  Professor  Griscom  of  Paris,  as 
already  noted,  furnished  notes  of  interesting  scientific 
discoveries  abroad.  Other  gentlemen  have  from  time  to 
time  acted  in  the  same  capacity.  The  most  prominent  of 
them  was  Professor  Jerome  Nickles  of  Nancy,  France, 
who  regularly  furnished  a  series  of  valuable  notes  on 
varied  subjects,  chiefly  from  foreign  sources,  extending 
from  1852  to  1869.  On  the  latter  date  he  met  an  untimely 
death  in  his  laboratory  in  connection  with  experiments 
upon  hydrofluoric  acid  (47,  434,  1869). 

It  may  be  added,  further,  that  one  of  the  striking 
features  about  the  Journal,  especially  in  the  earlier  half 
century  of  its  existence,  is  the  personal  nature  of  many 
of  its  contributions,  which  were  very  frequently  in  the 
form  of  letters  written  to  Benjamin  Silliman  or  J.  D. 
Dana.  This  is  perhaps  but  another  reflection  of  the 
extent  to  which  the  growth  of  the  magazine  centered 
around  these  two  men,  whose  wide  acquaintance  and 
broad  scientific  repute  made  of  the  Journal  a  natural 
place  to  record  the  new  and  interesting  things  that  were 
being  discovered  in  science. 

The  following  list  gives  the  names  and  dates  of  ser- 
vice, as  recorded  on  the  Journal  title  pages,  of  the  gen- 
tlemen formally  made  Associate  Editors : 

Wolcott  Gibbs    ....(2)  11,  1851  to  (3)   18,  1879 

Asa  Gray ''  15,  1853  "     ''     34,  1887 

Louis  Agassiz   ''  16,  1853  ''    (2)  41,  1866 

Waldo  I.  Burnett ''  16,  1853  ''     ''     17,  1853 

George  J.  Brush ''  35,  1863  '^    (3)   18,  1879 

Samuel  W.  Johnson   "  35,  1863  ''     "     18,  1879 

Hubert  A.  Newton (2)  38,  1864  to  (4)     1,  1896 

Addison  E.  Verrill '*  47,  1869 

Alfred  M.  Mayer (3)  5,  1873  to  (3)     6,  1873 

Edward  C.  Pickering ''  7,  1874  ''     ''     13,  1877 

George  F.  Barker   ''  14,  1877  ''    (4)   29,  1910 

Josiah  P.  Cooke ''  14,  1877  ''    (3)  47,  1894 


54  A  CENTURY  OF  SCIENCE 

John  Trowbridge  (3)  19,  1880 

George  W.  Goodale  "  35,  1888 

Henry  S.  ■Williams   ''  47,  1894 

Henry  P.  Bowditch ''  49,  1895  to  (4)     8,  1899 

William  G.  Farlow   "  49,  1895 

Othniel  C.  Marsh "  49,  1895  to  (4)     6,  1899 

Henry  A.  Rowland  (4)  1,  1896  "     ''     10,  1900 

Joseph  S.  Diller ''  1,  1896 

Louis  V.  Pirsson ''  7,  1899 

William  M.  Davis  ''  9,  1900 

Joseph  S.  Ames  "  12,  1901 

Horace  L.  Wells ''  18,  1904 

Herbert  E.  Gregory ''  18,  1904 

Horace  S.  Uhler ''  33,  1912 

Present  and  Future  Conditions, 

The  field  to  be  occupied  by  the  ^^  American  Journal  of 
Science  and  Arts/'  as  seen  by  its  founder  in  1818  and 
presented  by  him  in  the  first  number,  as  quoted  entire  on 
an  earlier  page,  was  as  broad  as  the  entire  sphere  of 
science  itself.  It  thus  included  all  the  departments  of 
both  pure  and  applied  science  and  extended  even  to  music 
and  fine  arts  also.  As  the  years  went  by,  however,  and 
the  practical  applications  of  science  greatly  increased, 
technical  journals  started  up,  and  the  necessity  of  culti- 
vating this  constantly  expanding  field  diminished.  It 
was  not,  however,  until  January,  1880,  that  '^the  Arts'' 
ceased  to  be  a  part  of  the  name  by  which  the  Journal 
was  known. 

About  the  same  date  also — or  better  a  little  earlier — ■ 
began  an  increasing  development  of  scientific  research, 
particularly  as  fostered  by  the  graduate  schools  of  our 
prominent  universities.  The  full  presentation  of  this 
subject  would  require  much  space  and  is  indeed  unneces- 
sary as  the  main  facts  must  be  distinct  in  the  mind  of  the 
reader.  It  is  only  right,  however,  that  the  large  part 
played  in  this  movement  by  the  Johns  Hopkins  Univer- 
sity (founded  in  1876)  should  be  mentioned  here. 

As  a  result  of  this  movement,  which  has  been  of  great 
benefit  in  stimulating  the  growth  of  science  in  the 
country,  many  new  journals  of  specialized  character  have 
come  into  existence  from  time  to  time.  Further  local- 
ization and  specialization  of  scientific  publication  have 


AMERICAN  JOURNAL  OF  SCIENCE 


55 


resulted  from  the  increased  activity  of  scientific  societies 
and  academies  at  numerous  centers  and  the  springing 
into  existence  thereby  of  new  organs  of  publication 
through  them,  as  also  through  certain  of  the  Government 
Departments,  the  Carnegie  Institution,  and  certain  uni- 
versities and  museums. 

As  bearing  upon  this  subject,  the  following  list  of  the 
more  prominent  scientific  periodicals  started  in  this 
country  since  1867  is  not  without  interest : 

1867-        .  American  Naturalist. 

1875-        .  Botanical  Bulletin;   later  Botanical  Gazette. 

1879-1913.  American  Chemical  Journal. 

1880-1915.  School  of  Mines  Quarterly. 

1883-        .  Science. 

1885-        .  Journal  of  Heredity. 

1887-        .  Journal  of  Morphology. 

1887-1908.  Technology  Quarterly. 

1888-1905.  American  Geologist. 

1891-        .  Journal  of  Comparative  Neurology. 

1893-        .  Journal  of  Geology, 

1893-        .  Physical  Eeview. 

1895-  .  Astrophysical  Journal. 

1896-  .  Journal  of  Physical  Chemistry. 
1896-        .  Terrestrial  Magnetism. 
1897-1899.  Zoological  Bulletin;    followed  by 

1900-  .     Biological  Bulletin. 

1901-  .    American  Journal  of  Anatomy. 
1904r-        .     Journal  of  Experimental  Zoology. 

1905-  .  Economic  Geology. 

1906-  .  Anatomical  Eecord. 

1907-  .  Journal  of  Economic  Entomology. 
1911-  .  Journal  of  Animal  Behavior. 
1914-  .  American  Journal  of  Botany. 
1916-  .  Genetics. 

1918-        .    American  Journal  of  Physical  Anthropology. 

The  result  of  the  whole  movement  has  been  of  neces- 
sity to  narrow,  little  by  little,  the  sphere  of  a  general 
scientific  periodical  such  as  the  Journal  has  been  from 
the  beginning.  The  exact  change  might  be  studied  in 
detail  by  tabulating  as  to  subjects  the  contents  of  succes- 
sive volumes,  decade  by  decade,  from  1870  down.  It  is 
sufficient,  here,  however,  to  recognize  the  general  fact 
that  while  the  number  of  original  papers  published  in  the 


56  A  CENTURY  OF  SCIENCE 

periodicals  of  this  country,  in  1910,  for  example,  was  very 
many  times  what  it  was  in  1825,  a  large  part  of  these 
have  naturally  found  their  home  in  periodicals  devoted 
to  the  special  subject  dealt  with  in  each  case.  That  this 
movement  will  continue,  though  in  lessened  degree  now 
that  the  immediate  demand  is  measurably  satisfied,  is  to 
be  expected.  At  the  same  time  it  has  not  seemed  wise,  at 
any  time  in  the  past,  to  formally  restrict  the  pages  of  the 
Journal  to  any  single  group  of  subjects.  The  future  is 
before  us  and  its  problems  will  be  met  as  they  arise.  At 
the  moment,  however,  there  seems  to  be  still  a  place  for  a 
scientific  monthly  sufficiently  broad  to  include  original 
papers  of  important  general  bearing  even  if  special  in 
immediate  subject.  In  this  way  it  would  seem  that 
**Silliman's  JournaP'  can  best  continue  to  meet  the 
ideals  of  its  honored  founder,  modified  as  they  must  be  to 
meet  the  change  of  conditions  which  a  century  of  scien- 
tific investigation  and  growth  have  wrought.  Incident- 
ally it  is  not  out  of  place  to  add  that  a  self-supporting, 
non-subsidized  scientific  periodical  may  hope  to  find  a 
larger  number  of  subscribers  from  among  the  workers  in 
science  and  the  libraries  if  it  is  not  too  restricted  in  scope. 

The  last  subject  touched  upon  introduces  the  essential 
matter  of  financial  support  without  which  no  monthly 
publication  can  survive.  With  respect  to  the  periodicals 
of  recent  birth,  listed  above,  it  is  safe  to  say  that  some 
form  of  substantial  support  or  subsidy — often  very  gen- 
erous— is  the  rule,  perhaps  the  universal  one.  This  has 
never  been  the  case  with  the  American  Journal.  The 
liberality  and  broad-minded  attitude  of  Yale  College  in 
the  early  days,  and  of  the  Yale  University  that  has  devel- 
oped from  it,  have  never  been  questioned.  At  the  same 
time  the  special  conditions  have  been  such  as  to  make  it 
desirable  that  the  responsibility  of  meeting  the  financial 
requirements  should  be  carried  by  the  editors-in-chief. 
At  present  the  Yale  Library  gives  adequate  payment  for 
certain  publications  received  by  the  Journal  in  exchange, 
though  for  many  years  they  were  given  to  it  as  a  matter 
of  course,  free  of  charge.  Beyond  this  there  is  nothing 
approaching  a  subsidy. 

The  difficulties  on  the  financial  side  met  with  by  the  elder 
Silliman  have  been  suggested,  although  not  adequately 


AMERICAN  JOURNAL  OF  SCIENCE  57 

presented,  in  the  various  statements  quoted  from  early 
volumes.  The  same  problems  in  varying  degree  have 
continued  for  the  past  sixty  years.  Since  1914  they  have 
been  seriously  aggravated  for  reasons  that  need  not  be 
enlarged  upon.  Prior  to  that  date  the  subscription  list 
had,  for  reasons  chiefly  involved  in  the  development  of 
special  journals,  been  much  smaller  than  the  number 
estimated  by  Silliman,  for  example,  in  volume  50  (p.  xiv), 
although  there  has  been  this  partial  compensation  that 
the  considerable  number  of  well-established  libraries  on 
the  subscription  list  has  meant  a  greater  degree  of  sta- 
bility and  a  smaller  proportion  of  bad  accounts.  The 
past  four  years,  however,  the  Journal,  with  all  simi- 
lar undertakings  here  and  elsewhere,  has  been  compelled 
to  bear  its  share  of  the  burden  of  the  world  war  in  dimin- 
ished receipts  and  greatly  increased  expenses.  It  is 
gratifying  to  be  able  to  acknowledge  here  the  generosity 
of  the  authors,  or  of  the  laboratories  with  which  they 
have  been  connected,  in  their  willingness  not  infrequently 
to  give  assistance,  for  example,  in  the  payment  of  more 
or  less  of  the  cost  of  engravings,  or  in  a  few  special  cases 
a  large  portion  of  the  total  cost  of  publication.  In  this 
way  the  problem  of  ways  and  means,  constantly  before 
the  editor  who  bears  the  sole  responsibility,  has  been 
simplified. 

It  should  also  be  stated  that  as  those  immediately 
interested  have  looked  forward  to  the  present  anniver- 
sary, it  has  been  with  the  hope  that  this  occasion  might  be 
an  appropriate  one  for  the  establishment  of  a  *' Silliman 
Fund'*  to  commemorate  the  life  and  work  of  Benjamin 
Silliman.  The  income  of  such  a  fund  would  lift  from 
the  University  the  burden  that  must  unavoidably  fall 
upon  it  when  the  responsibility  for  the  conduct  of  the 
Journal  can  no  longer  be  carried  by  members  of  the  fam- 
ily including  the  editor  and — as  in  years  long  past — a 
silent  partner  whose  aid  on  the  business  side  has  been 
essential  to  the  efficiency  and  economy  of  the  enterprise. 
Present  conditions  are  not  favorable  for  such  a  move- 
ment, although  something  has  been  already  accomplished 
in  the  desired  direction.  At  the  present  time  every 
patriotic  citizen  must  feel  it  his  first  duty  to  give  his  sav- 
ings as  well  as  his  spare  income  to  the  support  of  the 


58  A  CENTURY  OF  SCIENCE 

National  Government  in  the  world  struggle  for  freedom 
in  which  it  is  taking  part.  But,  whatever  the  exact  con- 
dition of  the  future  may  be,  it  cannot  be  questioned  that 
the  Journal  founded  by  Benjamin  Silliman  in  1818  will 
survive  and  will  continue  to  play  a  vital  part  in  the  sup- 
port and  further  development  of  science. 

The  present  year  of  1918  finds  the  world  at  large,  and 
with  it  the  world  of  .science,  painfully  crushed  beneath  the 
overwhelming  weight  of  a  world  war  of  unprecedented 
severity.  The  four  terrible  years  now  nearly  finished 
have  seen  a  fearful  destruction  of  life  and  property  which 
must  have  a  sad  influence  on  the  progress  of  science  for 
many  years  to  come.  Only  in  certain  restricted  lines  has 
there  been  a  partial  compensation  in  the  stimulating 
influence  due  to  the  immediate  necessities  connected  with 
the  great  conflict.  One  hundred  years  ago  ^  ^  the  reign  of 
war''  was  keenly  in  the  mind  of  the  editor  in  beginning 
his  work,  but  for  him,  happily,  the  long  period  of  the 
Napoleonic  wars  was  already  in  the  past,  as  also  the  brief 
conflict  of  1812,  in  which  this  country  was  engaged  and  in 
which  Silliman  himself  played  a  minor  part.  We,  too, 
must  believe,  no  matter  how  serious  the  outlook  of  the 
present  moment,  that  a  fundamental  change  will  come  in 
the  not  distant  future;  the  nations  of  the  world  must 
sooner  or  later  turn  once  more  to  peaceful  pursuits  and 
the  scientific  men  of  different  races  must  become  again 
not  enemies  but  brothers  engaged  in  the  common  cause 
of  uplifting  human  life.  The  peace  that  we  look  forward 
to  to-day  is  not  for  this  country  alone,  but  a  peace  which 
shall  be  a  permanent  blessing  to  the  entire  world  for 
ages  to  come. 

Note. — The  portrait  which  forms  the  frontispiece  of 
this  volume  has  been  reproduced  from  the  plate  in 
volume  50  (1847).  The  original  painting  was  made  by 
H.  Willard  in  1835,  when  Silliman  was  in  Boston 
engaged  in  delivering  the  Lowell  lectures ;  he  was  then 
nearly  fifty-six  years  of  age.  The  engraving,  as  he 
states  elsewhere,  was  made  from  this  painting  for  the 
Yale  Literary  Magazine,  and  was  published  in  the  num- 
ber for  December,  1839. 


AMERICAN  JOURNAL  OF  SCIENCE  59 

It  is  interesting  to  quote  the  remarks  with  which  the 
editor  introduces  the  portrait  (50,  xviii,  1847).    He  says : 

The  portrait  prefixed  to  this  volume  was  engraved  for  a  very 
different  purpose  and  for  others  than  the  patrons  of  this  Jour- 
nah  It  has  heen  suggested  hy  friends,  whose  judgment  we  are 
accustomed  to  respect,  that  it  ought  to  find  a  place  here,  since  it 
is  regarded  as  an  authentic,  although,  perhaps,  a  rather  austere 
resemblance.  In  yielding  to  this  suggestion,  it  may  he  sufficient 
to  quote  the  sentiment  of  Cowper  on  a  similar  occasion,  who 
remarked — ''that  after  a  man  has,  for  many  years,  turned  his 
mind  inside  out  before  the  world,  it  is  only  affectation  to  attempt 
to  hide  his  face/' 

Notes, 

^  The  statements  given  are  necessarily  much  condensed,  without  an 
attempt  to  follow  all  changes  of  title;  furthermore,  the  dates  of  actual 
publication  for  the  academies  given  above  are  often  somewhat  vaguely 
recorded.  For  fuller  information  see  Scudder's  *' Catalogue  of  Scientific 
Serials,  1633-1876,"  Cambridge,  1876;  also  H.  Carrington  Bolton's 
*' Catalogue  of  Scientific  and  Technical  Periodicals,  1665-1882"  (Smith- 
sonian Institution,  1885).  The  writer  is  much  indebted  to  Mr.  C.  J.  Barr, 
Assistant  Librarian  of  Yale  University  Library,  for  his  valuable  assistance 
in  this  connection. 

^  The  following  footnote  accompanies  the  opening  article  of  the  first 
volume  of  the  Journal.  *'From  the  MS.  papers  of  the  Connecticut  Acad- 
emy, now  published  by  permission."  Similar  notes  appear  elsewhere. 
Ed. 


II 

A  CENTURY  OF  GEOLOGY THE  PROGRESS 

OF  HISTORICAL.  GEOLOGY  IN  NORTH 
AMERICA 

By  CHARLES  SCHUCHERT 

Introduction, 

THE  American  Journal  of  Science,  '*one  of  the 
greatest  influences  in  American  geology/^  founded 
in  1818,  has  published  a  little  more  than  92,000 
pages  of  scientific  matter.  Of  geology,  including  min- 
eralogy, there  appear  to  be  upward  of  20,000  pages. 
What  a  vast  treasure  house  of  geologic  knowledge  is 
stored  in  these  194  volumes,  and  how  well  the  editors 
have  lived  up  to  their  proposed  *^plan  of  work''  as 
stated  in  the  opening  volume,  where  Silliman  says :  ^  ^  It 
is  designed  as  a  deposit  for  original  American  communi- 
cations" in  **the  physical  sciences  .  .  .  and  especially 
our  mineralogy  and  geology''  (1,  v,  1818) !  Not  only  is 
it  the  oldest  continuously  published  scientific  journal  of 
this  country,  but  it  has  proved  itself  to  be  *^  perhaps  the 
most  important  geological  periodical  in  America"  (Mer- 
rill). It  is  impossible  to  adequately  present  in  this 
memorial  volume  of  the  Journal  the  contents  of  the 
articles  on  the  geological  sciences. 

Editor  Silliman  was  not  only  the  founder  of  the  Jour- 
nal, but  the  generating  center  for  the  making  of 
geologists  and  promoting  geology  during  the  rise  of  this 
science  in  America.  For  nearly  three  decades,  the  work- 
ers came  to  him  for  counsel  and  help,  and  he  had  a  kind 
paternal  word  for  them  all.  This  influence  is  also  shown 
in  the  many  letters  which  were  addressed  to  him,  and 
which  he  published  in  the  Journal.  A  similar  influence, 
paternal  care,  and  constructive  criticism  were  continued 


HISTORICAL  GEOLOGY  61 

by  James  D.  Dana,  and  especially  in  his  earlier  career 
as  editor. 

Not  including  mineralogy,  there  are  in  the  Journal 
upward  of  1500  distinct  articles  on  geology.  Of  these, 
over  400  are  on  vertebrate  paleontology,  about  325  on 
invertebrate  paleontology,  and  90  on  paleobotany.  Of 
articles  bearing  on  historical  geology  there  are  about  160, 
and  on  stratigraphic  geology  more  than  360.  In  addition 
to  all  this,  there  are  more  than  2000  pages  of  geologic 
matter  relating  to  books  and  of  letters  communicated  to 
the  editors  Silliman  and  Dana.  We  may  summarize  with 
Doctor  MerrilPs  statement  in  his  well-known  Contribu- 
tions to  the  History  of  American  Geology : 

*'From  its  earliest  inception  geological  notes  and  papers 
occupied  a  prominent  place  in  its  pages,  and  a  perusal  of  the 
numbers  from  the  date  of  issue  down  to  the  present  time  will, 
alone,  afford  a  fair  idea  of  the  gradual  progress  of  American 
geology." 

Before  presenting  a  synopsis  of  the  more  important 
steps  in  the  progress  of  historical  geology  in  America,  it 
will  be  well  to  introduce  a  rapid  survey  of  the  rise  of 
geology  in  Europe,  for,  after  all,  American  geology  grew 
out  of  that  of  England,  France  and  Germany.  This 
dependence  was  conspicuously  true  during  the  first 
four  decades  of  the  previous  century.  With  the  rise  of 
the  first  New  York  State  Survey  (1836-1843)  and  that 
of  Pennsylvania  (1836-1844,  1858),  American  geology 
became  more  or  less  independent  of  Europe.  Finally, 
this  article  will  conclude  with  a  survey  of  the  rise  of 
paleometeorology,  paleogeography,  evolution,  and  inver- 
tebrate paleontology. 

The  Mise  of  Geology  in  Europe, 

Mineral  Geology. — The  geological  sciences  had  their 
rise  in  the  study  of  minerals  as  carried  on  by  the  German 
chemist  and  physician  George  Bauer  (1494-1555),  better 
known  as  Agricola.  Bauer  originated  the  critical  study 
of  minerals,  but  did  not  distinguish  his  ^'fossilia,''  the 
remains  of  organisms,  from  the  inorganic  crystal  forms. 
Mineral  geology  endured  until  the  close  of  the  eighteenth 
century. 


62  A  CENTURY  OF  SCIENCE 

Cosmogonists. — Then  came  the  expounders  of  the 
earth's  origin,  the  cosmogonists  of  the  sixteenth  to  the 
end  of  the  eighteenth  centuries.  The  fashion  of  this 
time  was  to  write  histories  of  the  earth  derived  out  of 
the  imagination. 

Earliest  Historical  Geology. — Even  though  Giovanni 
Arduino  (1713-1795)  of  Padua  was  not  the  first  to 
classify  the  rocks  into  three  series  according  to  their 
age,  he  did  this  more  clearly  than  any  one  else  before  his 
time.  The  rocks  about  Verona  he  grouped  in  1759  into 
Primary,  Secondary,  Tertiary,  and  Volcanic.  This 
three-fold  classification  came  into  general  use,  though 
modified  with  time. 

Early  in  the  nineteenth  century  it  had  become  plain 
that  formations  of  very  varying  ages  were  included  in 
each  one  of  the  three  series.  Through  the  study  of  the 
fossils  and  the  recognition  of  the  fact  that  mountain 
ranges  have  been  raised  at  various  times,  causing 
younger  f ossilif erous  strata  to  take  on  the  characters  of 
the  Primary,  it  was  seen  that  these  terms  of  Arduino  had 
lost  their  original  significance. 

The  first  one  to  describe  in  detail  a  local  stratigraphic 
sequence  was  Johann  Gottlob  Lehmann  (died  1767). 
In  1756  he  published  **one  of  the  classics  of  geological 
literature,"  distinguishing  clearly  thirty  successive  sedi- 
mentary deposits,  some  of  which  he  said  had  fossils,  but 
he  did  not  use  them  to  distinguish  the  strata. 

What  Lehmann  did  for  the  Permian  system,  George 
Christian  Fiichsel  (1722-1773)  did  even  better  for  the 
Triassic  of  Thuringia,  in  1762  and  1773.  He  pointed  out 
not  only  the  sequence,  but  also  how  the  gently  inclined 
strata  rest  upon  the  older  upturned  masses  of  the  moun- 
tains ;  also  that  some  formations  have  only  marine  fos- 
sils, while  others  have  only  terrestrial  forms  and  thus 
indicate  the  proximity  of  land.  The  deformed  strata  he 
thought  had  fallen  into  the  hollows  within  the  earth, 
great  caverns  that  had  also  consumed  much  of  the 
oceanic  waters  and  had  in  so  doing  greatly  lowered 
the  sea-level.  It  was  Ftichsel  who  first  introduced  the 
theory  of  universal  formations,  and  who  defined  the  term 
formation,  using  it  as  we  now  do,  system  or  period. 
Even  though  Lehmann  and  Fiichsel  showed  that  there 


HISTORICAL  GEOLOGY  63 

was  a  definite  order  and  process  in  the  formation  of  the 
earth's  crust,  their  example  was  barren  of  followers  until 
the  beginning  of  the  eighteenth  century. 

Wernerian  Geology  or  Geognosy. — We  come  now  to 
the  time  of  Abraham  Gottlob  Werner  (1749-1817),  who 
from  1775  to  1817  was  professor  of  mining  and  mineral- 
ogy in  the  Freiberg  Academy  of  Mines.  Geikie,  in  his 
most  interesting  Founders  of  Geology,  says  that  Werner 
**  bulks  far  more  largely  in  the  history  of  geology  than 
any  of  those  with  whom  up  to  the  present  we  have  been 
concerned — a  man  who  wielded  an  enormous  author- 
ity over  the  mineralogy  and  geology  of  his  day.'' 
'* Although  he  did  great  service  by  the  precision  of  his 
lithological  characters  and  by  his  insistence  on  the  doc- 
trine of  geological  succession,  yet  as  regards  geological 
theory,  whether  directly  by  his  own  teaching,  or  indi- 
rectly by  the  labors  of  his  pupils  and  followers,  much  of 
his  influence  was  disastrous  to  the  higher  interests  of 
geology.'' 

Werner  arranged  the  crust  of  the  earth  into  a  series  of 
formations,  as  had  been  done  previously  by  Lehmann 
and  Fiichsel,  and  one  of  his  fundamental  postulates  was 
that  all  rocks  were  chemically  precipitated  in  the  ocean 
as  ** universal  formations."  For  this  reason  Werner's 
school  were  called  the  Neptunists.  Nowhere,  however, 
did  he  explain  how  and  where  the  deep  and  primitive 
ocean  had  disappeared. 

According  to  Werner,  the  first  formed  or  oldest  rocks 
were  the  chemically  deposited  Primitive  strata,  including 
granite  and  other  igneous  and  metamorphic  rocks.  On 
these  followed  the  Transition  rocks,  the  earliest  sedi- 
ments of  mechanical  origin,  and  above  them  the  Floetz 
rocks,  a  term  for  the  horizontal  stratified  rocks.  These 
last  he  said  were  partly  of  chemical  but  chiefly  of  mechan- 
ical origin.     Last  of  all  came  the  Alluvial  series. 

The  existence  of  volcanoes  had  been  pointed  out  long 
before  Werner's  time  by  the  Italian  school  of  geologists, 
but  as  for  **the  universality  and  potency  of  what  is  now 
termed  igneous  action,"  all  was  *^ brushed  aside  by  the 
oracle  of  Freiberg."  Reactions  between  the  interior 
and  exterior  of  our  earth  **were  utterly  antagonistic  to 
Werner's  conception  of  the  structure  and  history  of  the 


64  A  CENTUEY  OF  SCIENCE 

earth."  To  him,  volcanoes  were  ^'burning  mountains'' 
that  arose  from  the  combustion  of  subterranean  beds  of 
coal,  spontaneously  ignited. 

The  breaking  down  of  the  Wernerian  doctrines  began 
with  two  of  Werner's  most  distinguished  pupils,  D'Au- 
buisson  de  Voisins  (1769-1819)  and  Von  Buch.  The 
former  in  1803  had  accepted  Werner's  aqueous  origin  of 
basalt,  but  after  studying  the  celebrated  and  quite  recent 
volcanic  area  of  Auvergne  he  recanted  in  1804.  Here  he 
saw  the  basaltic  rocks  lying  upon  and  cutting  through 
granite,  and  in  places  more  than  1200  feet  thick.  *^If 
these  basaltic  rocks  were  lavas,"  says  Geikie,  *Hhey 
must,  according  to  the  Wernerian  doctrine,  have  resulted 
from  the  combustion  of  beds  of  coal.  But  how  could  coal 
be  supposed  to  exist  under  granite,  which  was  the  first 
chemical  precipitate  of  a  primeval  ocean?" 

Leopold  von  Buch  (1774-1853),  *Hhe  most  illustrious 
geologist  that  Germany  has  produced,"  after  two  years 
spent  in  Norway  was  satisfied  **that  the  rocks  in  the 
Christiania  district  could  not  be  arranged  according  to 
the  Wernerian  plan,  which  there  completely  broke  down. 
Von  Buch  found  a  mass  of  granite  lying  among 
fossiliferous  limestones  which  were  manifestly  meta- 
morphosed, and  were  pierced  by  veins  of  granite,  por- 
phyry, and  syenite."  Even  so,  he  was  not  ready  to 
abandon  the  teachings  of  his  master.  After  a  study 
of  the  mountain  systems  of  Germany,  however,  *'he 
declared  that  the  more  elevated  mountains  had  never 
been  covered  by  the  sea,  as  Werner  had  taught,  but  were 
produced  by  successive  ruptures  and  uplifts  of  the  ter- 
restrial crust"  (Geikie). 

Rise  of  Geology  and  Conformism. — Modern  geology 
has  its  rise  in  James  Hutton  (1726-1797)  of  Edinburgh, 
Scotland.  In  1785  and  1795,  Hutton  published  his 
Theory  of  the  Earth,  with  Proofs  and  Illustrations.  His 
'immortal  theory"  is  his  only  work  on  geology.  ** For- 
tunately for  Hutton 's  fame  and  for  the  onward  march  of 
geology,  the  philosopher  numbered  among  his  friends  the 
illustrious  mathematician  and  natural  philosopher,  John 
Playfair  (1748-1819),  who  had  been  closely  associated 
with  him  in  his  later  years,  and  was  intimately  con- 
versant with  his  geological  opinions."    In  1802,  Play- 


HISTORICAL  GEOLOGY  65 

fair  published  his  Illustrations  of  the  Huttonian  Theory 
of  the  Earth,  of  which  Geikie  says,  **0f  this  great  classic 
it  is  impossible  to  speak  too  highly,''  as  it  is  at  the  basis 
of  all  modern  geology. 

One  of  Hutton's  fundamental  doctrines  is  that  the 
earth  is  internally  hot  and  that  in  the  past  large  masses 
of  molten  material,  the  granites,  have  been  intruded  into 
the  crust.  It  was  these  igneous  views  that  led  to  his 
followers  being  called  the  Plutonists.  Another  of  his 
great  doctrines  was  that  ^*the  ruins  of  an  earlier  world 
lie  beneath  the  secondary  strata, ' '  and  that  they  are  sep- 
arated by  what  is  now  known  as  unconformity.  He 
clearly  recognized  a  lost  interval  in  the  broken  relation 
of  the  structures,  and  that  the  ruins,  the  detrital  mate- 
rials, of  one  world  after  another  are  superposed  in  the 
structure  of  the  earth. 

Hutton  also  held  that  the  deformation  of  once  horizon- 
tally deposited  strata  was  probably  brought  about  at  dif- 
ferent periods  by  great  convulsions  that  shook  the  very 
foundations  of  the  earth.  After  a  convulsion,  there  was 
a  long  time  of  erosion,  represented  by  the  unconformity. 
Geikie  says,  *^The  whole  of  the  modern  doctrine  of 
earth  sculpture  is  to  be  found  in  the  Huttonian  theory. ' ' 

The  Lyellian  doctrine  of  metamorphism  had  its  origin 
in  Hutton,  for  he  showed  that  invading  igneous  granite 
had  altered,  through  its  heat  and  expanding  power,  the 
originally  water-laid  sediments,  and  that  the  schists  of 
the  Alps  had  been  born  of  the  sea  like  other  strati- 
fied rocks. 

Hutton  is  the  father  of  the  Uniformitarian  principle, 
for  he  ^*  started  with  the  grand  conception  that  the  past 
history  of  our  globe  must  be  explained  by  what  can  be 
seen  to  be  happening  now,  or  to  have  happened  only 
recently.  The  dominant  idea  in  his  philosophy  is  that 
the  present  is  the  key  to  the  past.''  This  principle  has 
been  impressed  on  all  later  geologists  by  Sir  Charles 
Lyell,  and  is  the  chief  cornerstone  of  modern  geology. 

The  principle  of  uniformitarianism  has  underlain 
geologic  interpretation  since  the  days  of  Hutton,  Play- 
fair,  and  Lyell.  However,  it  is  often  applied  too  rigidly 
in  interpretations  based  upon  the  present  conditions, 
because  in  the  past  there  were  long  times  when  the  topo- 


QQ  A  CENTURY  OF  SCIENCE 

graphic  features  of  the  earth  were  very  different  from 
those  of  to-day.  Throughout  the  Paleozoic,  and,  less 
markedly,  the  Mesozoic,  the  oceans  flooded  the  lands 
widely  (at  times  over  60  per  cent  of  the  total  area),  high- 
lands were  inconspicuous,  sediments  far  scarcer,  and 
climates  warm  and  equable  throughout  the  world.  High- 
land conditions,  and  especially  the  broadly  emergent  con- 
tinents of  the  present,  were  only  periodically  present  in 
the  Paleozoic  and  then  for  comparatively  short  intervals 
between  the  periods.  Therefore  rates  of  denudation, 
solution,  sedimentation,  and  evolution  have  varied 
greatly  throughout  the  geological  ages.  These  differ- 
ences, however,  relate  to  degrees  of  operation,  and  not  to 
kinds  of  processes;  but  the  differences  in  degree  of 
operation  react  mightily  on  our  views  as  to  the  age  of 
the  earth. 

Geologic  time  had,  for  Hutton,  no  ^Westige  of  a  begin- 
ning, no  prospect  of  an  end.''  In  other  words,  geologic 
time  is  infinite.  He  did  not,  however,  discover  a  method 
by  which  the  chronology  of  the  earth  could  be  determined. 

First  Important  Text-hoolcs. — In  1822  appeared  the 
ablest  text-book  so  far  published,  and  the  pattern  for 
most  of  the  later  ones.  Outlines  of  the  Geology  of  Eng- 
land and  Wales,  by  W.  D.  Conybeare  (1787-1857)  and  W. 
Phillips  (1775-1828).  **In  this  excellent  volume  all  that 
was  then  known  regarding  the  rocks  of  the  country,  from 
the  youngest  formations  down  to  the  Old  Eed  Sandstone, 
was  summarized  in  so  clear  and  methodical  a  manner  as 
to  give  a  powerful  impulse  to  the  cultivation  of  geology 
in  England"  (Geikie).  This  book  is  reviewed  at  great 
length  by  Edward  Hitchcock  in  the  Journal  (7, 203, 1824). 

To  indicate  how  far  historical  geology  had  progressed 
up  to  1822  in  England,  a  digest  of  the  geological  column 
as  presented  in  this  text-book  is  given  in  the  following 
table,  along  with  other  information. 

A  text-book  writer  of  yet  greater  influence  was  Charles 
Lyell  (1797-1875),  whose  Principles  of  Geology  appeared 
in  three  volumes  between  1830  and  1833.  This  and  his 
other  books  were  kept  up  to  date  through  many  editions, 
and  his  Elements  of  Geology  is,  as  Geikie  says,  ''the  hand 
book  of  every  English  geologist''  working  with  the  fos- 
siliferous  formations. 


HISTORICAL  GEOLOGY  67 

The  Rise  of  Geology  in  North  America, 

The  Generating  Centers. — In  America,  geology  had  its 
rise  independently  in  three  places :  in  the  two  scientific 
societies  of  Boston  and  Philadelphia,  and  dominantly  in 
Benjamin  Silliman  of  Yale  College.  Stated  in  another 
way,  we  may  say  that  geology  in  America  had  its  origin 
in  the  following  pioneers  and  founders :  first,  in  William 
Maclure  at  Philadelphia,  and  next  in  Benjamin  Silliman 
at  New  Haven.  Through  the  influence  of  the  latter, 
Amos  Eaton,  the  botanist,  became  a  geologist  and  taught 
geology  at  Williams  College  and  later  at  the  Rensselaer 
School  in  Troy,  New  York.  Through  the  same  influence 
Rev.  Edward  Hitchcock  also  became  a  geologist  and 
taught  the  subject  after  1825  at  Amherst  College. 

Silliman  was  the  first  to  take  up  actively  the  teach- 
ing of  mineralogy  and  geology  based  on  collections  of 
specimens.  He  spread  the  knowledge  in  popular  lectures 
throughout  the  Eastern  States,  graduated  many  a^  stu- 
dent in  the  sciences,  making  of  some  of  them  professional 
teachers  and  geologists,  provided  all  with  a  journal 
wherein  they  could  publish  their  research,  organized  the 
first  geological  society  and  through  his  students  the  first 
official  geological  surveys,  and  by  kind  words  and  acts 
stimulated,  fostered,  and  held  together  American  scien- 
tific men  for  fifty  years.  Of  him  it  has  been  truly  said 
that  he  was  '*the  guardian  of  American  science  from  its 
childhood. ' ' 

The  American  Academy  in  Boston. — The  second  oldest 
scientific  society,  but  the  first  one  to  publish  on  geological 
subjects,  was  the  American  Academy  of  Arts  and 
Sciences  of  Boston,  instituted  and  publishing  since  1780. 
Up  to  the  time  of  the  founding  of  this  Journal,  there  had 
appeared  in  the  publications  of  the  American  Academy 
about  a  dozen  papers  of  a  geologic  character,  none  of 
which  need  to  be  mentioned  here  excepting  one  by  S.  L. 
and  J.  F.  Dana,  entitled  *' Outlines  of  the  Mineralogy  and 
Geology  of  Boston,"  published  in  1818.  This  is  an  early 
and  important  step  in  the  elucidation  of  one  of  the  most 
intricate  geologic  areas,  and  is  further  noteworthy  for  its 
geologic  map,  the  third  one  to  appear,  the  older  ones 
being  by  Maclure  and  Hitchcock  (Merrill). 


The  Geological  Column  in  1822 


Present  American 

C.&P. 

Wer- 

Other 

classification 

Conybeare  and  Phillips  1822 

orders 

nerian 
orders 

writ- 
ers 

Psychozoic  or  Recent 

Alluvial 

QQ 
02 

QD 

ci 

Pleistocene 

Diluvial 

O 

"i 

3 

.sa 

S=l[Neogene 

Upper   Marine    formation    (Crag, 

S 

s 

£• 

o 

Bagshot  sand,  and  Isle  of  Wight) 

r^ 

■| 

B 

Freshwater  formations 

K 

O 

6 

&np«>-««- 

London  Clay 
Plastic  Clay 

3 

1 

^ 

Cretaceous 

Chalk 

Beds   between    Chalk    and  Oolite 

Comanchian  1887 

Series  (Chalk  Marie,  Green  Sand, 
Weald  Clay,  Iron  Sand) 

r 

Upper    Oolitic    division    (Purbeck 

S 

OQ 

o 

beds,  Portland  Oolite,  Kimmer- 

1 

03 

QQ 

g 

idge  Clay) 
Middle  Oolitic  division  (Coral  Rag, 

o 

m 

c§ 

g 

c3 

J 

o 

1 

Oxford  Clay) 

O 

>» 

Jurassic  1829 

Lower  Oolitic  division  (Cornbrash, 

^ 

Stonesfield  Slate,  Forest  Marble, 

g 

1 

Great  Oolite,  Fullers'  Earth,  In- 

O. 

s 

ferior  Oolite,  Sand  and  Marie- 

S 
Ul 

ci 

stone 

Lias 

Triassic  1834 

New  Red  Sandstone 

Magnesian  Limestone 
Coal  Measures 

n3 

Permian  1841 

1 

o^^ 

.2 

Pennsyivanian  1891 

13  go 

1 

Mississippian  1869 

Millstone  Grit  and  Shale 

i%^ 

fl 

s 

Devonian  1839 
Silurian  1835 

Old  Red  Sandstone 

15 1 

o 

1 

2 

1 

Ordovician  1879 

H 

(-Lower  Silurian  1835) 

1— H 

Cambrian  1833 

Unresolved 
Submedial 

> 

.2 

Keweenawan^    S 

^ 

o 

Animikian      I  g  S 

•| 

I 

^ 

Huronian        \    U^ 

g 

d 

1 

Sudburian      J   ^ 

and 

■fi 

6                                   -^  iS 

^.S     Keewatin         1  gS 

Inferior  Orders 

g  g     Coutchiching  j  g  g 

HISTORICAL  GEOLOGY  69 

Early  Geology  in  Philadelphia, — The  oldest  scientific 
society  is  the  American  Philosophical  Society  of  Phila- 
delphia, started  by  the  many-sided  Benjamin  Franklin  in 
1769,  and  which  has  published  since  1771.  Up  to  the  time 
of  the  founding  of  the  Journal  in  1818,  there  had 
appeared  in  the  publications  of  this  society  thirteen 
papers  of  a  geologic  nature,  nearly  all  small  building 
stones  in  the  rising  geologic  story  of  North  America. 
The  only  fundamental  ones  were  Maclure  's  Observations 
of  1809  and  1817.  Later,  in  this  same  city,  there  was 
organized  another  scientific  society  that  came  to  be  for 
a  long  time  the  most  active  one  in  America.  This  was 
the  Academy  of  Natural  Sciences,  started  in  1812  with 
seven  members,  but  it  was  not  until  1817  and  the  election 
of  William  Maclure  as  its  first  president  that  the  work 
of  the  Academy  was  of  a  far-reaching  character.  Here 
was  built  up  not  only  a  society  for  the  advancement  of  the 
natural  sciences  and  publications  for  the  dissemination 
of  such  knowledge,  but,  what  is  equally  important,  the 
first  large  library  and  general  museum. 
^  William  Maclure  (1763-1840),  correctly  named  by  Sil- 
liman  the  ''father  of  American  geology,"  was  born  and 
educated  in  Scotland,  and  died  near  Mexico  City.  A 
merchant  of  London  until  1796,  when  he  had  already 
amassed  ''a  considerable  fortune,"  he  made  a  first  short 
visit  to  New  York  City  in  1782.  In  1796  he  again  came 
to  America,  this  time  to  become  a  citizen  of  this  country 
and  a  liberal  patron  of  science. 

About  1803,  single-handed  and  unsustained  by  gov- 
ernment patronage,  Maclure  interested  himself  most 
zealously  and  efficiently  in  American  geology.  In  1809 
he  published  his  Observations  on  the  Geology  of  the 
United  States,  Explanatory  of  a  Geological  Map.^  This 
work  he  revised  ''on  a  yet  more  extended  scale,"  issuing 
it  in  1817  with  130  pages  of  text,  accompanied  by  a  large 
colored  geological  map. 

Silliman,  the  Pioneer  Promoter  of  Geology. — ^In  1806 
when  Benjamin  Silliman  (1779-1864)  began  actively  to 
teach  chemistry  and  mineralogy,  all  the  sciences  in  Amer- 
ica were  in  a  very  backward  state,  and  the  earth  sciences 
were  not  recognized  as  such  in  the  curricula  of  any  of  our 
colleges.     Silliman  gave  his  first  lecture  in  chemistry  on 


70  A  CENTURY  OF  SCIENCE 

April  4, 1804.  In  the  summer  of  that  year,  Yale  College 
asked  him  to  go  to  England  to  purchase  material  for  the 
College,  and  great  possibilities  for  broadening  his 
knowledge  now  loomed  before  him.  As  Silliman  himself 
(43,  225,  1842)  has  told  the  interesting  story  of  his 
sojourn  in  England  and  Scotland,  it  is  worth  while  to 
restate  a  part  of  it  here. 

**  Passing  over  to  England  in  the  spring  of  1805,  and  fixing 
my  residence  for  six  months  in  London,  I  found  there  no  school, 
public  or  private,  for  geological  instruction,  and  no  association 
for  the  cultivation  of  the  science,  which  was  not  even  named  in 
the  English  universities.''  In  geology  *' Edinburgh  was  then 
far  in  advance  of  London  .  .  .  Prof.  Jameson  having  recently 
returned  from  the  school  of  Werner,  fully  instructed  in  the  doc- 
trines of  his  illustrious  teacher,  was  ardently  engaged  to  maintain 
them,  and  his  eloquent  and  acute  friend,  the  late  Dr.  eTohn  Mur- 
ray, was  a  powerful  auxiliary  in  the  same  cause ;  both  of  these 
philosophers  strenuously  maintaining  the  ascendancy  of  the 
aqueous  over  the  igneous  agencies,  in  the  geological  phenomena 
of  our  planet. 

On  the  other  hand,  the  disciples  and  friends  of  Dr.  Hutton 
were  not  less  active.  He  died  in  1797,  and  his  mantle  fell  upon 
Sir  James  Hall,  who,  with  Prof.  Playfair  and  Prof.  Thomas 
Hope,  maintained  with  signal  ability,  the  igneous  theory  of 
Hutton.  It  did  not  become  one  who  was  still  a  youth  and  a 
novice,  to  enter  the  arena  of  the  geological  tournament  where 
such  powerful  champions  waged  war;  but  it  was  very  interest- 
ing to  view  the  combat,  well  sustained  as  it  was  on  both  sides, 
and  protracted,  without  a  decisive  issue,  into  a  drawn  battle  .  .  . 

The  conflicts  of  the  rival  schools  of  Edinburgh — the  Neptun- 
ists  and  the  Vulcanists,  the  Wernerians  and  the  Huttonians, 
were  sustained  with  great  zeal,  energy,  talent,  and  science ;  they 
were  indeed  marked  too  decidedly  by  a  partisan  spirit,  but  this 
very  spirit  excited  untiring  activity  in  discovering,  arranging, 
and  criticising  the  facts  of  geology.  It  was  a  transition  period 
between  the  epoch  of  geological  hypotheses  and  dreams,  which 
had  passed  by,  and  the  era  of  strict  philosophical  induction,  in 
which  the  geologists  of  the  present  day  are  trained    .    .    . 

I  was  a  diligent  and  delighted  listener  to  the  discussions  of 
both  schools.  Still  the  igneous  philosophers  appeared  to  me  to 
assume  more  than  had  been  proved  regarding  internal  heat. 
In  imagination  we  were  plunged  into  a  fiery  Phlegethon,  and  I 
was  glad  to  find  relief  in  the  cold  bath  of  the  Wernerian  ocean, 
where  my  predilections  inclined  me  to  linger.'' 


HISTORICAL  GEOLOGY  U 

Silliman's  Students  and  Their  Publications. — Silli- 
man's  first  student  to  take  up  geology  as  a  profession  was 
Denison  Olmstead  (1791-1859),  educator,  chemist,  and 
geologist,  who  was  graduated  from  Yale  in  1813.  Four 
years  later  he  was  under  special  preparation  with  Silli- 
man  in  mineralogy  and  geology,  and  in  that  year  was 
appointed  professor  of  chemistry  in  the  University  of 
North  Carolina.  In  1824-1825  Olmstead  issued  a  Report 
on  the  Geology  of  North  Carolina,  which  is  the  first  offi- 
cial geological  report  issued  by  any  state  in  America, 
^^a  conspicuous  and  solitary  instance,"  according  to 
Hitchcock  ^s  review  of  it  (14,  230,  1828),  *4n  which  any 
of  our  state  governments  have  undertaken  thoroughly  to 
develop  their  mineral  resources. ' ' 

Amos  Eaton  (1776-1842),  lawyer,  botanist,  surveyor, 
and  one  of  the  founders  of  American  geology,  was  a 
graduate  of  Williams  College  in  the  class  of  1799.  He 
studied  with  Silliman  in  1815,  attending  his  lectures  on 
chemistry,  geology,  and  mineralogy.  He  also  enjoyed 
access  to  the  libraries  of  Silliman  and  of  the  bot- 
anist, Levi  Ives,  in  which  works  on  botany  and  materia 
medica  were  prominent,  and  was  a  diligent  student  of  the 
College  cabinet  of  minerals.  He  settled  as  a  lawyer  and 
land  agent  in  Catskill,  New  York,  and  here  in  1810  he 
gave  a  popular  course  of  lectures  on  botany,  believed  to 
have  been  the  first  attempted  in  the  United  States. 

In  1818  appeared  Eaton's  first  noteworthy  geological 
publication,  the  Index  to  the  Geology  of  the  Northern 
States,  a  text-book  for  the  classes  in  geology  at  "Williams- 
town.  The  controlling  principle  of  this  book  was  Wer- 
nerism,  a  false  doctrine  from  which  Eaton  was  never 
able  to  free  himself.  This  book  was  ^*  written  over 
anew"  and  published  in  1820. 

While  at  Albany  in  1818,  Governor  De  Witt  Clinton 
asked  Eaton  to  deliver  a  course  of  lectures  on  chemistry 
and  geology  before  the  members  of  the  legislature  of 
New  York.  It  is  believed  that  Eaton  is  the  only  Ameri- 
can having  this  distinction,  and  because  of  it  he  became 
acquainted  with  many  leading  men  of  the  state,  inter- 
esting them  in  geology  and  its  application  to  agriculture 
by  means  of  surveys.     In  this  way  was  sown  the  idea 


T2  A  CENTURY  OF  SCIENCE 

which  eventually  was  to  fructify  in  that  great  official 
work:  The  Natural  History  of  New  York.  (See  43,  215, 
1842;  and  Youmans'  sketch  of  Eaton's  life,  Pop.  Sci. 
Monthly,  Nov.  1890.) 

Edward  Hitchcock  (1793-1864),  reverend,  state  geolo- 
gist, college  president,  and  another  of  the  founders  of 
American  geology,  was  largely  self-taught.  Previous  to 
1825,  when  he  entered  the  theological  department  of  Yale 
College,  he  had  met  Amos  Eaton,  who  interested  him 
in  botany  and  mineralogy,  and  between  1815  and  1819 
he  had  made  lists  of  the  plants  and  minerals  found  about 
his  native  town,  Deerfield,  Massachusetts.  Therefore, 
while  studying  theology  at  Yale  it  was  natural  for  him 
also  to  take  up  mineralogy  and  geology  with  Silliman, 
whose  acquaintance  he  had  made  at  least  as  early  as  1818. 

Hitchcock,  who  was  destined  to  be  one  of  the  most 
prominent  figures  of  his  time,  was  appointed  in  1825  to 
the  chair  of  chemistry  and  natural  history  at  Amherst 
College.  His  first  geologic  paper,  one  of  five  pages, 
appeared  in  1815.  Three  years  later  appeared  his  more 
important  paper  on  the  Geology  and  Mineralogy  of  a 
Section  of  Massachusetts,  New  Hampshire,  and  Vermont 
(1,  105,  436,  1818).  This  is  also  noteworthy  for  its 
geological  map,  the  next  one  to  be  published  after  those 
of  Maclure  of  1809  and  1817.  In  1823  came  a  still 
greater  work,  A  Sketch  of  the  Geology,  Mineralogy,  and 
Scenery  of  the  Regions  contiguous  to  the  River  Connecti- 
cut (6,  1,  200,  1823;  7,  1,  1824).  Here  the  map  above 
referred  to  was  greatly  improved,  and  the  survey  was 
one  of  the  most  important  of  the  older  publications. 

Youmans  in  his  account  of  Hitchcock  (Pop.  Sci. 
Monthly,  Sept.  1895)  says: 

"The  State  of  Massachusetts  commissioned  him  to  make  a 
geological  survey  of  her  territory  in  1830.  Three  years  were 
spent  in  the  explorations,  and  the  work  was  of  such  a  high  char- 
acter that  other  States  were  induced  to  follow  the  example  of 
Massachusetts  .  .  .  The  State  of  New  York  sought  his  advice 
in  the  organization  of  a  survey,  and  followed  his  suggestions, 
particularly  in  the  division  of  the  territory  into  four  parts,  and 
appointed  him  as  the  geologist  of  the  first  district.  He  entered 
upon  the  work,  but  after  a  few  days  of  labor  he  found  that  he 
must  necessarily  be  separated  from  his  family,  much  to  his  dis- 


HISTORICAL  GEOLOGY  73 

inclination.  He  also  conceived  the  idea  of  urging  a  more  thor- 
ough survey  of  his  own  State  ,•  hence  he  resigned  his  commission 
and  returned  home.  The  effort  for  a  resurvey  of  Massachusetts 
was  successful,  and  he  was  recommissioned  to  do  the  work.  The 
results  appeared  in  1841  and  1844." 

Oliver  P.  Hubbard  was  assistant  to  Silliman  in  1831- 
1836,  and  then  up  to  1866  taught  chemistry,  mineralogy, 
and  geology  at  Dartmouth  College.  James  G.  Percival 
was  graduated  at  Yale  in  1815,  and  in  1835  he  and  C.  U. 
Shepard  of  Amherst  College  were  appointed  state  geol- 
ogists of  Connecticut.     Their  report  was  issued  in  1842. 

James  Dwight  Dana  (1813-1895)  was  undoubtedly  the 
ablest  of  all  of  Silliman 's  students.  Graduated  at  Yale 
in  1833,  he  spent  fifteen  months  in  the  United  States 
Navy  as  instructor  in  mathematics,  cruising  oif  France, 
Italy,  Greece,  and  Turkey.  In  1836  he  was  assistant  to 
Silliman,  and  in  1837,  at  the  age  of  twenty-four  years, 
he  published  his  widely  used  System  of  Mineralogy. 
Two  years  later  Dana  joined  the  Wilkes  Exploring  Expe- 
dition as  mineralogist,  returning  to  America  in  1842 ;  his 
geological  results  of  this  expedition  were  published  in 
1849.  In  1863,  during  the  Eebellion,  he  published  his 
Manual  of  Geology,  and  through  four  editions  it 
remained  for  forty  years  the  standard  text-book  for 
American  geologists. 

First  American  Geological  Society. — The  founding  in 
1807  of  the  Geological  Society  of  London,  the  parent  of 
geological  societies,  undoubtedly  had  its  stimulating 
effect  on  Silliman,  and  with  his  marked  organizing  ability 
be  began  to  think  of  forming  an  American  society  of  the 
same  kind.  This  he  brought  about  the  year  following 
the  appearance  of  the  Journal,  that  is,  in  1819.  The 
American  Geological  Society,  begun  in  1819  (1,  442, 
1819),  was  terminated  in  1830  (17,  202,  1830).  The  first 
meeting  (September  6,  1819)  and  all  the  subsequent  ones 
were  held  in  the  cabinet  of  Yale  College.^  The  brief 
records  of  the  doings  of  this  society  are  printed  in  vol- 
umes 1,  10,  15,  and  18  of  the  Journal.  Silliman  was  the 
attraction  at  the  meetings,  surrounded  by  his  mineral 
cabinet,  and  he  gave  **the  true  scientific  dress  to  all  the 
naked  mineralogical  subjects''  discussed. 


U  A  CENTURY  OF  SCIENCE 

Wernerian  Geology  in  North  America, 

The  Father  of  American  Geology. — Historical  Geology- 
begins  in  America  with  William  Maclure's  Observations 
on  the  Geology  of  the  United  States,  issued  in  1809. 
This  was  the  first  important  original  work  on  North 
American  geology,  and  its  colored  geological  map  was  the 
first  one  of  the  area  east  of  the  Mississippi  River.  The 
classification  was  essentially  the  Wernerian  system.  All 
of  the  strata  of  the  Coastal  Plain,  now  known  to  range 
from  the  Lower  Cretaceous  to  Recent,  were  referred  to 
the  Alluvial.  To  the  west,  over  the  area  of  the  Piedmont, 
were  his  Primitive  rocks,  while  the  older  Paleozoic 
formations  of  the*  Appalachian  ranges  were  referred  to 
-the  Transition.  West  of  the  folded  area,  all  was  Floetz 
or  Secondary,  or  what  we  now  know  as  Paleozoic  sedi- 
mentaries.  The  Triassic  of  the  Piedmont  area  and  that 
of  Connecticut  he  called  the  Old  Red  Sandstone,  and  the 
coal  formations  of  the  interior  region  he  said  rested  upon 
the  Secondary.  The  second  edition  of  the  work  in  1817 
was  much  improved,  along  with  the  map,  which  was  also 
printed  on  a  more  correct  geographic  base.  (For  greater 
detail,  see  Merrill,  Contributions  to  the  History  of 
American  Geology,  1906.) 

Even  though  Maclure's  geologic  maps  are  much  gen- 
eralized, and  the  scheme  of  classification  adopted  a  very 
broad  one,  they  are  in  the  main  correct,  even  if  they  do 
emphasize  unduly  the  rather  simple  geologic  structure 
of  North  America.  This  fact  is  patent  all  through 
Maclure's  description.  Cleaveland  also  refers  to  it  in 
his  treatise  of  1816,  and  Silliman  in  the  opening  volume 
of  the  Journal  (1,  7, 1818)  says :  **The  outlines  of  Amer- 
can  geology  appear  to  be  particularly  grand,  simple,  and 
instructive. ' '  Then,  all  the  kinds  of  rocks  were  compre- 
hended under  four  classes.  Primitive,  Transition,  Allu- 
vial, and  Volcanic.  It  is  also  interesting  to  note  here 
that  in  1822  Maclure  had  lost  faith  in  the  aqueous  origin 
of  the  igneous  rocks  and  writes  of  the  Wernerian  system 
as  '^fast  going  out  of  fashion"^  (5,  197,  1822),  while 
Hitchcock  said  about  the  same  thing  in  1825  (9,  146). 

The  Work  of  Eaton. — Amos  Eaton,  after  traveling 
10,000  miles  and  completing  his  Erie  Canal  Report  in 


HISTOEICAL  GEOLOGY  75 

1824,  *' reviewed  the  whole  line  several  times,''  and  pub- 
lished in  1828  in  the  Journal  (14,  145)  a  paper  on  Geolog- 
ical Nomenclature,  Classes  of  Rocks,  etc.  The  broader 
classification  is  the  Wernerian  one  of  Primitive,  Transi- 
tion, and  Secondary  classes.  Under  the  first  two  he  has 
fossiliferous  early  Paleozoic  formations,  but  does  not 
know  it,  because  he  pays  no  attention  anywhere  to  the 
detail  of  the  entombed  fossils,  and  all  of  his  Secondary 
is  what  we  now  call  Paleozoic.  The  correlations  of  the 
latter  are  faulty  throughout. 

Then  came  his  paper  of  1830,  Geological  Prodromus 
(17,  63),  in  which  he  says:  '*!  intend  to  demonstrate 
.  .  .  that  all  geological  strata  are  arranged  in  ^ve  analo- 
gous series ;  and  that  each  series  consists  of  three  forma- 
tions; viz.,  the  Carboniferous  [meaning  mud-stones], 
Quartzose,  and  Calcareous.''  We  seem  to  see  here 
expressed  for  the  first  time  the  idea  of  *^  cycles  of  sedi- 
mentation," but  Eaton  does  not  emphasize  this  idea,  and 
the  localities  given  for  each  '^formation"  of  ** analogous 
series ' '  demonstrate  beyond  a  doubt  that  he  did  not  have 
a  sedimentary  sequence.  The  whole  is  simply  a  jumble 
of  unrelated  formations  that  happen  to  agree  more  or 
less  in  their  physical  characters. 

**I  intend  to  demonstrate,"  he  says  further,  ''that 
the  detritus  of  New  Jersey,  embracing  the  marie,  which 
contains  those  remarkable  fossil  relics,  is  antediluvial,  or 
the  genuine  Tertiary  formation."  This  correlation  had 
been  clearly  shown  by  Finch  in  1824  (7,  31)  and  yet  both 
are  in  error  in  that  they  do  not  distinguish  the  included 
Cretaceous  marls  and  greensands  as  something  apart 
from  the  Tertiary. 

One  gets  impatient  with  the  later  writings  of  Eaton, 
because  he  does  not  become  liberalized  with  the  progres- 
sive ideas  in  stratigraphic  geology  developing  first  in 
Europe  and  then  in  America,  especially  among  the  geolo- 
gists of  Philadelphia.  Therefore  it  is  not  profitable  to 
follow  his  work  further. 

Early  American  Text-hoohs  of  Geology, — The  first 
American  text-book  of  geology  bears  the  date  of  Boston 
1816  and  is  entitled  An  Elementary  Treatise  on  Mineral- 
ogy and  Geology,  its  author  being  Parker  Cleaveland  of 
Bowdoin  College.     The  second  edition  appeared  in  1822. 


T6  A  CENTUEY  OF  SCIENCE 

It  also  had  a  geologic  map  of  the  United  States,  practi- 
cally a  copy  of  Maclure  's.  To  mineralogy  were  devoted 
585  pages,  and  to  geology  55,  of  which  37  describe  rocks 
and  5  the  geology  of  the  United  States.  The  chronology 
is  Wernerian.  Of  ^'geological  systems''  there  are  two, 
*' primitive  and  secondary  rocks.'' 

In  1818  appeared  Amos  Eaton's  Index  to  the  Geology 
of  the  Northern  States,  having  54  pages,  and  in  1820 
came  the  second  edition,  *' wholly  written  over  anew," 
with  286  pages.  The  theory  of  the  later  edition  is  still 
that  of  "Werner,  with  *  improvements  of  Cuvier  and 
Bakewell,"  and  yet  one  sees  nowadays  but  little  in  it  of 
the  far  better  English  text-book.  Eaton  did  very  little 
to  advance  philosophic  geology  in  America.  What 
is  of  most  value  here  are  his  personal  observations  in 
regard  to  the  local  geology  of  western  Massachusetts, 
Connecticut,  southwestern  Vermont,  and  eastern  New 
York  (1,  69, 1819;  also  MerrHl,  p.  234).  ^ 

We  come  now  to  the  most  comprehensive  and  advanced 
of  the  early  text-books  used  in  America.  This  is  the 
third  English  edition  of  Eobert  Bakewell 's  Introduction 
to  Geology  (400  pages,  1829),  and  the  first  American  edi- 
tion **with  an  Appendix  Containing  an  Outline  of  his 
Course  of  Lectures  on  Geology  at  Yale  College,  by  Ben- 
jamin Silliman"  (128  pages).  Bakewell 's  good  book  is 
in  keeping  with  the  time,  and  while  not  so  advanced  as 
Conybeare  and  Phillips's  Outlines  of  1822,  yet  is  far 
more  so  than  Silliman's  appendix.  The  latter  is  general 
and  not  specific  as  to  details ;  it  is  still  decidedly  Wer- 
nerian, though  in  a  modified  form.  Silliman  says  he  is 
*' neither  Wernerian  nor  Huttonian,"  and  yet  his  sum- 
mary on  pages  120  to  126  shows  clearly  that  he  was  not 
only  a  Wernerian  but  a  pietist  as  well. 

Unearthing  of  the  Cenozoic  and  Mesozoic 
in  North  America, 

The  Discerning  of  the  Tertiary. — The  New  England 
States,  with  their  essentially  igneous  and  metamorphic 
formations,  could  not  furnish  the  proper  geologic  envi- 
ronment for  the  development  of  stratigraphers  and 
paleontologists.  So  in  America  we  see  the  rise  of  such 
geologists  first  in  Philadelphia,  where  they  had  easy 


HISTOEICAL  GEOLOGY  77 

access  to  the  horizontal  and  highly  f  ossilif  erous  strata  of 
the  coastal  plain.  The  first  one  to  attract  attention  was 
Thomas  Say,  after  him  came  John  Finch,  followed  by 
Lardner  Vanuxem,  Isaac  Lea,  Samuel  G.  Morton,  and 
T.  A.  Conrad.  These  men  not  only  worked  out  the 
succession  of  the  Cenozoic  and  the  upper  part  of  the 
Mesozoic,  but  blazed  the  way  among  the  Paleozoic  strata 
as  well. 

Thomas  Say  (1787-1834),  in  1819,  was  the  first  Ameri- 
can to  point  out  the  chronogenetic  value  of  fossils  in  his 
article.  Observations  on  some  Species  of  Zoophytes, 
Shells,  etc.,  principally  Fossil  (1,  381).  He  correctly 
states  that  the  progress  of  geology  *^must  be  in  part 
founded  on  a  knowledge  of  the  different  genera  and 
species  of  reliquiae,  which  the  various  accessible  strata  of 
the  earth  present."  Say  fully  realizes  the  difiiculties  in 
the  study  of  fossils,  because  of  their  fragmental  charac- 
ter and  changed  nature,  and  that  their  correct  interpre- 
tation requires  a  knowledge  of  similar  living  organisms. 

The  application  of  what  Say  pointed  out  came  first  in 
John  Finch's  Geological  Essay  on  the  Tertiary  Forma- 
tions in  America  (7,  31,  1824).  Even  though  the  paper 
is  still  laboring  under  the  mineral  system  and  does  not 
discern  the  presence  of  Cretaceous  strata  among  his  Ter- 
tiary formations,  yet  Finch  also  sees  that  ^ ^fossils  con- 
stitute the  medals  of  the  ancient  world,  by  which  to  ascer- 
tain the  various  periods." 

Finch  now  objects  to  the  wide  misuse  in  America  of 
the  term  alluvial  and  holds  that  it  is  applied  to  what  is 
elsewhere  known  as  Tertiary.     He  says : 

**  Geology  will  achieve  a  triumph  in  America,  when  the  term 
alluvial  shall  be  banished  from  her  Geological  Essays,  or  con- 
fined to  its  legitimate  domain,  and  then  her  tertiary  formations 
will  be  seen  to  coincide  with  those  of  Europe,  and  the  formations 
of  London,  Paris,  and  the  Isle  of  Wight,  will  find  kindred  asso- 
ciations in  Virginia,  the  Carolinas,  Georgias,  the  Floridas,  and 
Louisiana." 

The  formations  as  he  has  them  from  the  bottom 
upwards  are:  (1)  Ferruginous  sand,  (2)  Plastic  clay, 
(3)  Calcaire  Silicieuse  of  the  Paris*  Basin,  (4)  London 
Clay,  (5)  Calcaire  Ostree,  (6)  Upper  marine  formation, 
(7)  DHuvial. 


78  A  CENTURY  OF  SCIENCE 

The  grandest  of  these  early  stratigraphic  papers, 
however,  is  that  by  Lardner  Vanuxem  (1792-1848}^  of 
only  three  pages,  entitled  **Eemarks  on  the  Characters 
and  Classification  of  Certain  American  Eock  Forma- 
tions" (16,  254, 1829).  Vannxem,  a  cautious  man  and  a 
profound  thinker,  had  been  educated  at  the  Paris  School 
of  Mines.  James  Hall  told  the  writer  in  a  conversation 
that  while  the  first  New  York  State  Survey  was  in  oper- 
ation, all  of  its  members  looked  to  Vanuxem  for  advice. 

In  the  paper  above  referred  to,  Vanuxem  points  out  in 
a  very  concise  manner  that ; 

**The  alluvial  of  Mr.  Maclure  .  .  .  contains  not  only  well 
characterized  alluvion,  but  products  of  the  tertiary  and  second- 
ary classes.  Littoral  shells,  similar  to  those  of  the  English  and 
Paris  basins,  and  pelagic  shells,  similar  to  those  of  the  chalk 
deposition  or  latest  secondary,  abound  in  it.  These  two  kinds 
of  shells  are  not  mixed  with  each  other ;  they  occur  in  different 
earthy  matter,  and,  in  the  southern  states  particularly,  are  at 
different  levels.  The  incoherency  or  earthiness  of  the  mass,  and 
our  former  ignorance  of  the  true  position  of  the  shells,  have  been 
the  sources  of  our  erroneous  views." 

The  second  error  of  the  older  geologists,  according  to 
Vanuxem,  was  the  extension  of  the  secondary  rocks  over 
**the  western  country,  and  the  back  and  upper  parts  of 
New  York."  They  are  now  called  Paleozoic.  Some  had 
even  tried  to  show  the  presence  of  Jurassic  here  because 
of  the  existence  of  oolite  strata.  *^It  was  taken  for 
granted,  that  all  horizontal  rocks  are  secondary,  and  as 
the  rocks  of  these  parts  of  the  United  States  are  horizon- 
tal in  their  position,  so  they  were  supposed  to  be  second- 
ary." He  then  shows  on  the  basis  of  similar  Ordovician 
fossils  that  the  rocks  of  Trenton  Falls,  New  York,  recur 
at  Frankfort  in  Kentucky,  and  at  Nashville  in  Tennessee. 

*^It  is  also  certain  that  an  uplifting  or  downf ailing 
force,  or  both,  have  existed,  but  it  is  not  certain  that 
either  or  both  these  forces  have  acted  in  a  uniform  man- 
ner. .  .  .  Innumerable  are  the  facts,  which  have  fallen 
under  my  observation,  which  show  the  fallacy  of  adopt- 
ing inclination  for  the  character  of  a  class,"  such  as  the 
Transition  class  of  strata.  He  then  goes  on  to  say  that 
in  the  interior  of  our  country  the  so-called  secondary 
rocks  are  horizontal  and  in  the  mountains  to  the  east  the 


HISTORICAL  GEOLOGY  79 

same  strata  are  highly  inclined.  *'The  analogy,  or  iden- 
tity of  rocks,  I  determine  by  their  fossils  in  the  first 
instance,  and  their  position  and  mineralogical  characters 
in  the  second  or  last  instance." 

It  appears  that  Isaac  Lea  (1792-1886)  in  his  Contri- 
butions to  Geology,  1833,  was  the  first  to  transplant  to 
America  Lyell's  terms.  Pliocene,  Miocene,  and  Eocene, 
proposed  the  previous  year.  The  celebrated  Claiborne 
locality  was  made  known  to  Lea  in  1829,  and  in  the  work 
here  cited  he  describes  from  it  250  species,  of  which  200 
are  new.  The  horizon  is  correlated  with  the  London 
Clay  and  with  the  Calcaire  Grossier  of  France,  both  of 
Eocene  time  (25,  413, 1834). 

Timothy  A,  Conrad  began  to  write  about  the  Ameri- 
can Tertiary  in  1830,  and  his  more  important  publica- 
tions were  issued  at  Philadelphia.  His  papers  in  the 
Journal  begin  with  1833  and  the  last  one  on  the  Tertiary 
is  in  1846. 

The  Tertiary  faunas  and  stratigraphy  have  been 
modernized  by  William  H.  Dall  in  his  monumental  work 
of  1650  pages  and  60  plates  entitled  **  Contributions  to 
the  Tertiary  Fauna  of  Florida ' '  ( 1885-1903 ) .  Here  more 
than  3160  forms  of  the  Atlantic  and  Gulf  deposits  are 
described,  but  in  order  to  understand  their  relations  to 
the  fossil  faunas  elsewhere  and  to  the  living  world,  the 
author  studied  over  10,000  species.  Since  then,  many 
other  workers  have  interested  themselves  in  the  Tertiary 
problems.  Much  good  work  is  also  being  done  in 
the  Pacific  States  where  the  sequence  is  being  rapidly 
developed. 

The  Discerning  of  the  Eastern  Cretaceous. — The  Cre- 
taceous sequence  was  first  determined  by  that  ^*  active 
and  acute  geologist,"  Samuel  G.  Morton  (1799-1851),  but 
that  these  rocks  might  be  present  along  the  Atlantic 
border  had  been  surmised  as  early  as  1824  by  Edward 
Hitchcock  (7,  216).  Vanuxem,  as  above  pointed  out, 
indicated  the  presence  of  the  Cretaceous  in  1829.  In 
this  same  year  Morton  proved  its  presence  before  the 
Philadelphia  Academy  of  Natural  Sciences. 

Between  1830  and  1835  Morton  published  a  series  of 
papers  in  the  Journal  under  the  title  **  Synopsis  of  the 
Organic  Remains  of  the  Ferruginous  Sand  Formation  of 


80  A  CENTURY  OF  SCIENCE 

the  United  States,  with  Geological  Remarks''  (17,  274,  et 
seq.).  In  these  he  describes  the  Cretaceous  fossils  and 
demonstrates  that  the  ^'Diluvial"  and  Tertiary  strata  of 
the  Atlantic  border  also  have  a  long  sequence  of  Creta- 
ceous formations.  In  the  opening  paper  he  writes:  '*! 
consider  the  marl  of  New  Jersey  as  referable  to  the  great 
ferruginous  sand  series,  which  in  Prof.  Buckland's 
arrangement  is  designated  by  the  name  of  green  sand. 
...  On  the  continent  this  series  is  called  the  ancient 
chalk  .  .  .  lower  chalk,"  etc.  Again,  the  marls  of  New 
Jersey  are  **  geologically  equivalent  to  those  beds  which 
in  Europe  are  interposed  between  the  white  chalk  and 
the  Oolites."  This  correlation  is  with  the  European 
Lower  Cretaceous,  but  we  now  know  the  marls  to  be  of 
Upper  Cretaceous  age.  Although  Eaton  objected  stren- 
uously to  Morton's  correlation,  we  find  M.  Dufresnoy  of 
France  saying,  *^Your  limestone  above  green  sand 
reminds  me  very  much  of  the  Msestricht  beds,"  a  correla- 
tion which  stands  to  this  day  (22,  94, 1832).  In  1833  Mor- 
ton announces  that  the  Cretaceous  is  known  all  along  the 
Atlantic  and  Gulf  border,  and  in  the  Mississippi  valley. 
**The  same  species  of  fossils  are  found  throughout,"  and 
none  of  them  are  known  in  the  Tertiary.  He  now 
arranges  the  strata  of  the  former  ** Alluvial"  as  follows: 

Modem        \  ^^l^^^a,!. 
Moaem      ,  ^  Diluvial. 

{Upper  Tertiary  (Upper  Marine). 
Middle  Tertiary  (London  Clay). 
Lower  Tertiary  (Plastic  Clay), 
o         ,  \  Calcareous  Strata    /  Cretaceous  group,  or  Ferrugi- 

becondary   j  ferruginous  Sand  \      nous  Sand  series  (24,  128). 

Western  Cretaceous. — In  1841  and  1843  J.  N.  Nicollet 
announced  the  discovery  of  Cretaceous  in  the  Rocky 
Mountain  area.  Of  20  species  of  fossils  collected  by 
him,  4  were  said  to  occur  on  the  Atlantic  border,  and  of 
the  200  forms  of  the  Atlantic  slope  only  1  was  found  in 
Europe.  Here  we  see  pointed  out  a  specific  dissimilarity 
between  the  continents,  and  a  similarity  between  the 
American  areas  of  Cretaceous  deposits  (41, 181;  45,  153). 

The  Cretaceous  of  the  Rocky  Mountains  was  clearly 


HISTORICAL  GEOLOGY  81 

developed  by  F.  V.  Hayden  in  1855-1888  and  by  F.  B. 
Meek  (1857-1876).  Other  workers  in  this  field  were 
Charles  A.  White  (1869-1891),  and  R.  P.  Whitfield  (1877- 
1889).  Since  1891  T.  W.  Stanton  has  been  actively  inter- 
preting its  stratigraphy  and  faunas. 

Cretaceous  and  Comanche  of  Texas. — The  broader 
outlines  of  the  Cretaceous  of  Texas  had  been  described 
by  Ferdinand  Roemer  in  1852  in  his  good  work,  Kreide- 
bildungen  von  Texas,  but  it  was  not  until  1887  that 
Robert  T.  Hill  showed  in  the  Journal  (33,  291)  that  it 
included  two  great  series,  the  Gulf  series,  or  what  we  now 
call  Upper  Cretaceous,  and  a  new  one,  the  Comanche 
series.  This  was  a  very  important  step  in  the  right 
direction.  Since  then  the  Comanche  series  has  been 
regarded  by  some  stratigraphers  as  of  period  value, 
while  others  call  it  Lower  Cretaceous;  the  rest  of  the 
Texas  Cretaceous  is  divided  by  Hill  into  Middle  and 
Upper  Cretaceous.  On  the  other  hand,  Lower  Creta- 
ceous strata  had  been  proved  even  earlier  in  the  state  of 
California,  for  here  in  1869  W.  M.  Gabb  (1839-1878)  and 
J.  D.  Whitney  (1819-1896)  had  defined  their  Shasta 
group,  which  was  wholly  distinct  faunally  from  the 
Comanche  of  Texas  and  the  southern  part  of  the  Great 
Plains  country. 

Jurassic  and  Triassic  of  the  West. — In  1864,  the  Geo- 
logical Survey  of  California  proved  the  presence  of 
marine  Upper  Triassic  in  that  State,  and  since  then  it 
has  been  shown  that  not  only  is  all  of  the  Triassic  present 
in  Idaho  (where  it  has  been  known  since  1877),  Oregon, 
Nevada,  and  California,  but  that  the  Upper  Triassic  is 
of  very  wide  distribution  throughout  western  North 
America.  Jurassic  strata,  on  the  other  hand,  were  not 
shown  to  be  present  in  California  until  1885,  while  in  the 
Rocky  Mountain  area  of  the  United  States  there  was 
long  known  an  unresolved  series  of  '^Red  Beds'*  sit- 
uated between  the  Carboniferous  and  Cretaceous.  This 
gave  rise  to  the  **Red  Bed  problem,''  the  history  of 
which  is  given  by  C.  A.  White  in  the  Journal  (17,  214, 
1879).  In  1869,  F.  V.  Hayden  announced  the  discovery 
of  marine  Jurassic  fossils  in  this  series,  and  since  then 
they  have  come  to  be  known  as  the  Sundance  fauna, 
extending  from  southern  Utah  and  Colorado  into  Alaska. 


82  A  CENTURY  OF  SCIENCE 

Above  lie  the  dinosaur-bearing  fresh-water  deposits, 
since  1894  known  as  the  Morrison  beds.  In  1896,  0.  C. 
Marsh  (1831-1899)  announced  the  presence  of  Jurassic 
fresh-water  strata  along  the  Atlantic  coast  (2,  433),  but 
to-day  only  a  small  part  of  them  are  regarded  as  of  the 
age  of  the  Morrison,  while  the  far  greater  part  are 
referred  to  the  Comanche  or  Lower  Cretaceous.  The 
red  beds  below  the  Jurassic  of  the  Rocky  Mountain  area 
have  during  the  past  twenty  years  been  shown  to  be  in 
part  of  Upper  Triassic  age  and  of  fresh-water  origin, 
while  the  greater  lower  part  is  connected  with  the  Car- 
boniferous series  and  is  made  up  of  brackish-  and  fresh- 
water deposits  of  probable  Permian  time. 

Triassic  of  Atlantic  States. — The  fresh-water  Triassic 
of  the  Atlantic  border  states  was  first  mentioned  by 
Maclure  (1817),  who  regarded  it  as  the  equivalent  of  the 
Old  Red  Sandstone  of  Europe.  In  this  he  was  followed 
by  Hitchcock  in  1823  (6,  39),  the  latter  saying  that  above 
it  lies  **the  coal  formation,''  which  is  true  for  Europe, 
but  in  America  the  coal  strata  are  older  than  these  red 
beds,  now  known  to  be  of  Triassic  age. 

The  first  one  to  question  this  correlation  was  Alex- 
andre Brongniart,  who  had  received  from  Hitchcock  rock 
specimens  and  a  fossil  fish  which  he  erroneously  identi- 
fied with  a  Permian  species,  and  accordingly  referred 
the  strata  to  the  Permian  (3,  220, 1821 ;  6,  76,  pi.  9,  figs.  1, 
2,  1823).  The  discerning  Professor  Finch  in  1826 
remarked  that  the  red  beds  of  Connecticut  appear  to 
belong  *Ho  the  new  or  variegated  sandstone,"  because  of 
eight  different  criteria  that  he  mentions.  Of  these,  but 
two  are  of  value  in  correlation,  their  **  geological  posi- 
tion" and  the  presence  of  bones  other  than  fishes.  In 
the  Connecticut  area,  however,  the  geological  position 
cannot  be  determined  even  to-day,  and  in  Finch's  time 
the  bones  of  dinosaurs  were  unknown.  Finch  then  goes 
on  to  point  out  the  occurrences  of  Old  Red  Sandstone  in 
Pennsylvania,  but  all  of  the  places  he  refers  to  are  either 
younger  or  older  in  time.  Here  we  again  see  the  fatality 
of  trying  to  make  positive  correlations  on  the  basis  of 
lithology  and  color  (10,  209,  1826).  In  1835,  however, 
Hitchcock  showed  that  the  bones  that  had  been  found  in 
1820  were  those  of  a  saurian,  and  accordingly  referred 


HISTORICAL  GEOLOGY  83 

the  strata  of  the  Connecticut  valley  to  the  New  Red 
Sandstone,  a  term  that  then  covered  both  the  Permian 
and  the  Triassic.  In  1842,  W.  B.  Rogers  referred  the 
beds  to  the  Jurassic,  on  the  basis  of  plants  from  Virginia. 
In  1856,  W.  C.  Redfield  (1789-1857),  because  of  the  fishes, 
advocated  a  Lias,  or  Jurassic  age,  and  proposed  the 
name  Newark  group  for  all  the  Triassic  deposits  of 
the  Atlantic  border.  More  recently,  on  the  basis  of  the 
plants  studied  by  Newberry,  Fontaine,  Sturr,  and  Ward, 
and  the  vertebrates  described  by  Marsh  and  Lull,  the 
age  has  been  definitely  fixed  as  Upper  Triassic  (see 
Dana's  Manual  of  Geology,  740,  1895). 

Unearthing  of  the  Paleozoic  in  North  America, 

Permian  of  the  United  States, — In  Europe,  previous  to 
1841,  the  formations  now  classed  as  Permian  were 
included  in  the  New  Red  Sandstone,  and  with  the  Car- 
boniferous were  referred  to  the  Secondary.  In  that 
year  Murchison  proposed  the  period  term  Permian.  In 
1845  came  the  classic  Geology  of  Russia  in  Europe  and 
the  Ural  Mountains,  by  Murchison,  Keyserling,  and  De 
Verneuil.  In  this  great  work  the  authors  separated  out 
of  the  New  Red  the  Magnesian  Limestone  of  Great  Brit- 
ain and  the  Rothliegende  marls,  Kupferschiefer,  and 
Zechstein  of  Germany,  and  with  other  formations  of  the 
Urals  in  Russia,  referred  them  to  the  Permian  system. 
This  step,  one  of  the  most  discerning  in  historical  geol- 
ogy, was  all  the  more  important  because  they  closed  the 
Paleozoic  era  with  the  Permian,  beginning  the  Second- 
ary, or  Mesozoic,  with  the  New  Red  Sandstone  or  the 
Triassic  period.  There  is  a  good  review  of  this  work  bv 
D.  D.  Owen  (1807-1860)  in  the  Journal  for  1847  (3,  153). 

Owen,  though  accepting  the  Permian  system,  is  not 
satisfied  with  its  reference  to  the  Paleozoic,  and  he  sets 
the  matter  forth  in  the  Journal  (3,  365,  1847).  He 
doubts  *Hhe  propriety  of  a  classification  which  throws 
the  Permian  and  Carboniferous  systems  into  the  Paleo- 
zoic period."  This  is  mainly  because  there  is  no  ** evi- 
dence of  disturbance  or  unconformability"  between  the 
Permian  and  Triassic  systems.  Rather  *Hhere  is  so 
complete  a  blending  of  adjacent  strata''  that  it  is  only 


84  A  CENTURY  OF  SCIENCE 

in  Russia  that  the  Permian  has  been  distinguished  from 
the  Triassic.  This  view  of  Owen's  was  not  only  correct 
for  Russia  but  even  more  so  for  the  Alps  and  for  India, 
and  it  has  taken  a  great  deal  of  work  and  discussion  to 
fix  upon  the  disconformable  contact  that  distinguishes 
the  Paleozoic  from  the  Mesozoic  in  these  areas.  In 
other  words,  there  was  here  at  this  time  no  mountain 
making.  Then  Owen  goes  on  to  state  that  because  the 
Permian  of  Europe  has  reptiles,  he  sees  in  them  decisive 
Mesozoic  evidence.  **  These  are  certainly  strong  argu- 
ments in  favor  of  placing,  not  only  the  Permian,  but  also 
the  Carboniferous  group  in  the  Mesozoic  period,  and  ter- 
minating the  Paleozoic  division  with  the  commencement 
of  the  coal  measures."  To  this  harking  backward  the 
geologists  of  the  world  have  not  agreed,  but  have  fol- 
lowed the  better  views  of  Murchison  and  his  associates. 

In  1855  G.  G.  Shumard  discovered,  and  in  1860  his 
brother  B.  F.  Shumard  (1820-1869)  announced,  the 
presence  of  Permian  strata  in  the  Guadalupe  Mountains 
of  Texas,  and  in  1902  George  H.  Girty  (14,  363)  con- 
firmed this.  Girty  regards  the  faunas  as  younger  than 
any  other  late  Paleozoic  ones  of  America,  and  says: 
**For  this  reason  I  propose  to  give  them  a  regional  name, 
which  shall  be  employed  in  a  force  similar  to  Mississip- 
pian  and  Pennsylvanian.  .  .  .  The  term  Guadalupian  is 
suggested.'' 

G.  C.  Swallow  (1817-1899)  in  1858  was  the  first  to 
announce  the  presence  of  Permian  fossils  in  Kansas,  and 
this  led  to  a  controversy  between  himself  and  F.  B.  Meek, 
both  claiming  the  discovery.  It  is  only  in  more  recent 
years  that  it  has  been  generally  admitted  that  there  is 
Permian  in  that  state,  in  Oklahoma,  and  in  Texas.  This 
admission  came  the  more  readily  through  the  discovery 
of  many  reptiles  in  the  red  beds  of  Texas,  and  through 
the  work  of  C.  A.  White,  published  in  1891,  The  Texan 
Permian  and  its  Mesozoic  Types  of  Fossils  (Bull.  U.  S. 
Geological  Survey,  No.  77). 

Carboniferous  Formations, — The  coal  formations  are 
noted  in  a  general  way  throughout  the  earliest  volumes 
of  the  Journal.  The  first  accounts  of  the  presence  of 
coal,  in  Ohio,  are  by  Caleb  Atwater  (1,  227,  239,  1819), 
and  S.  P.  Hildreth   (13,  38,  40,  1828).     The  first  coal 


HISTORICAL  GEOLOGY  85 

plants  to  be  described  and  illustrated  were  also  from 
Ohio,  in  an  article  by  Ebenezer  Granger  in  1821  (3,  5-7). 
The  anthracite  field  was  first  described  in  1822  by  Zach- 
ariah  Cist  (4,  1)  and  then  by  Benjamin  Silliman  (10, 
331-351,  1826) ;  that  of  western  Pennsylvania  was 
described  by  WHliam  Meade  in  1828  (13,  32). 

The  Lower  Carboniferous  was  first  recognized  by  W. 
W.  Mather  in  1838  (34,  356).  Later,  through  the  work 
of  Alexander  Winchell  (1824-1891),  beginning  in  1862 
(33,  352)  and  continuing  until  1871,  and  through  the 
surveys  of  Iowa  (1855-1858),  Illinois  (essentially  the 
work  of  A.  H.  Worthen,  1858-1888),  Ohio  (1838,  Mather, 
etc.),  and  Indiana  (Owen,  etc.,  1838),  there  was  even- 
tually worked  out  the  following  succession: 

Permian  period. 

Upper  Barren  series. 
Dunkard  group. 
Washington  group. 
Pennsylvanian  period. 

Upper  Productive  Coal  series.    Monongahela  series. 
Lower  Barren  Coal  Measures.     Conemaugh  series. 
Lower  Productive  Coal  Measures.    Allegheny  series. 
Pottsville  series. 

The  New  York  System, — We  now  come  to  the  epochal 
survey  of  the  State  of  New  York,  one  that  established 
the  principles  of,  and  put  order  into,  American  strati- 
graphy from  the  Upper  Cambrian  to  the  top  of  the 
Devonian.  No  better  area  could  have  been  selected  for 
the  establishing  of  this  sequence.  This  survey  also 
developed  a  stratigraphic  nomenclature  based  on  New 
York  localities  and  rock  exposures,  and  made  full  use  of 
the  entombed  fossils  in  correlation.  Incidentally  it  devel- 
oped and  brought  into  prominence  James  Hall,  who  con- 
tinued the  stratigraphic  work  so  well  begun  and  who 
also  laid  the  foundation  for  paleontology  in  America, 
becoming  its  leading  invertebrate  worker. 

This  work  is  reviewed  at  great  length  in  the  Journal 
in  the  volumes  for  1844-1847  by  D.  D.  Owen.  Evidently 
it  followed  too  new  a  plan  to  receive  fulsome  praise  from 
conservative  Owen,  as  it  should  have.  He  remarks  that 
the  volumes  '*are  not  a  little  prolix,  are  voluminous  and 


86  A  CENTURY  OF  SCIENCE 

expensive,  and  do  not  give  as  clear  and  connected  a  view 
of  the  geological  features  of  the  state  as  could  be  wished. 
.  .  .  We  are  of  the  opinion  that  before  this  work  can 
become  generally  useful  and  extensively  circulated,  it 
must  be  condensed  and  arranged  into  one  compendious 
volume"  (46,  144,  1844).  This  was  never  done  and  yet 
the  work  was  everywhere  accepted  at  once,  and  to  this 
end  undoubtedly  Owen^s  detailed  review  helped  much. 

The  Natural  History  Survey  of  New  York  was  organ- 
ized in  1836  and  completed  in  1843.  The  state  was 
divided  into  four  districts,  and  to  these  were  finally 
assigned  the  following  experienced  geologists.  The 
southeastern  part  was  named  the  First  District,  with  W. 
W.  Mather  (1804-1859)  as  geologist;  the  northeastern 
quarter  was  the  Second  District,  with  Ebenezer  Emmons 
(1799-1863)  in  charge;  the  central  portion  was  the  Third 
District,  under  Lardner  Vanuxem  (1792-1848) ;  while 
the  western  part  was  James  Hall's  (1811-1898)  Fourth 
District.  Paleontology  for  a  time  was  in  charge  of  T.  A. 
Conrad  (1830-1877) ;  the  mineralogical  and  chemical  work 
was  in  the  hands  of  Lewis  C.  Beck;  the  botanist  was 
John  Torrey ;  and  the  zoologist  James  DeKay. 

The  New  York  State  Survey  published  six  annual 
reports  of  1675  pages  octavo,  and  four  final  geological 
reports  with  2079  pages  quarto.  Finally  in  1846 
Emmons  added  another  volume  on  the  soils  and  rocks 
of  the  state,  in  which  he  also  discussed  the  Taconic  and 
New  York  systems;  it  has  371  pages.  With  the  com- 
pletion of  the  first  survey,  Hall  took  up  his  life  work 
under  the  auspices  of  the  state — ^his  monumental  work. 
Paleontology  of  New  York,  in  fifteen  quarto  volumes  of 
4539  pages  and  1081  plates  of  fossils.  In  addition  to  all 
this,  there  are  his  annual  and  other  reports  to  the 
Eegents  of  the  State,  so  that  it  is  safe  to  say  that  he 
published  not  less  than  10,000  pages  of  printed  matter 
on  the  geology  and  paleontology  of  North  America. 

In  regard  to  this  great  series  of  works,  all  that  can  be 
presented  here  is  a  table  of  formations  as  developed  by 
the  New  York  State  Survey.  Practically  all  of  its 
results  and  formation  names  have  come  into  general  use, 
with  the  exception  of  the  Taconic  system  of  Emmons  and 
the  division  terms  of  the  New  York  system.    (See  p.  88.) 


HISTORICAL  GEOLOGY  87 

The  New  York  State  Survey,  begun  in  1836,  was  con- 
tinued by  James  Hall  from  1843  to  1898.  During  this 
time  he  was  also  state  geologist  of  Iowa  (1855-1858)  and 
Michigan  (1862).  Since  1898,  John  M.  Clarke  has  ably 
continued  the  Geological  Survey  of  New  York,  the  state 
which  continues  to  be,  in  science  and  more  especially  in 
geology  and  paleontology,  the  foremost  in  America. 

Western  Extension  of  the  New  York  system. — Before 
Hall  finished  his  final  report,  we  find  him  in  1841  on  **a 
tour  of  exploration  through  the  states  of  Ohio,  Indiana, 
Illinois,  a  part  of  Michigan,  Kentucky,  and  Missouri,  and 
the  territories  of  Iowa  and  Wisconsin.''  This  tour  is 
described  in  the  Journal  (42,  51,  1842)  under  the  caption 
*^ Notes  upon  the  Geology  of  the  Western  States.''  His 
object  was  to  ascertain  how  far  the  New  York  system  as 
the  standard  of  reference  **was  applicable  in  the  western 
extension  of  the  series."  In  a  general  way  he  was  very 
successful  in  extending  the  system  to  the  Mississippi 
Eiver,  and  he  clearly  saw  ^^a  great  diminution,  first  of 
sandy  matter,  and  next  of  shale,  as  we  go  westward,  and 
in  the  whole,  a  great  increase  of  calcareous  matter  in  the 
same  direction."  He  also  clearly  noted  the  warped 
nature  of  the  strata,  the  ^* anticlinal  axis,"  since  known 
as  the  Cincinnati  and  Wabash  uplifts  and  the  Ozark 
dome. 

Hall,  however,  fell  into  a  number  of  flagrant  errors 
because  of  a  too  great  reliance  on  lithologic  correlation 
and  supposedly  similar  sequence.  For  instance,  the 
Coal  Measures  of  Pennsylvania  were  said  to  directly 
overlap  the  Chemung  group  of  southern  New  York,  and 
now  he  finds  the  same  condition  in  Ohio,  Indiana,  and 
Illinois,  failing  to  see  that  in  most  places  between  the 
top  of  the  New  York  system  and  the  Coal  Measures  lay 
the  extensive  Mississippian  series,  one  that  he  generally 
confounded  with  the  Chemung,  or  included  in  the  *  ^  Car- 
boniferous group."  He  states  that  the  Portage  of  New 
York  is  the  same  as  the  Waverly  of  Ohio,  and  at  Louis- 
ville the  Middle  Devonian  waterlime  is  correlated  with 
the  similar  rock  of  the  New  York  Silurian.  Hall  was 
especially  desirous  of  fixing  the  horizon  of  the  Middle 
Ordovician  lead-bearing  rocks  of  Illinois,  Wisconsin,  arid 
Iowa,  but  unfortunately  correlated  them  with  the  Niag- 


88 


A  CENTURY  OF  SCIENCE 


The  Geological  Column  of  the  New  York  Geologists  of  1842-1843, 
according  to  W.  W.  Mather  1842. 

{Alluvial  division. 
Quaternary  division. 
Drift  division. 


Tertiary  system 


These  strata  are  included  in  the  next 
lower  division. 


Upper  Secondary 
system 


New  Ked  system 
>-  of  Emmons  and 
Hall. 


Long  Island  division.     Equals  the  Ter- 
tiary   and    Cretaceous    marls,    sands, 
and  clays  of  the  coastal  plain  of  New 
Jersey. 
Trappean  division. 

The  Palisades 
Red  Sandstone 
division. 

Coal  system  of  Mather,  and  Carboniferous  system  of  Hall. 
Old  Red  system  of  Catskill  Mountains  of  Emmons;    Catskill 
division  of  Mather  and  Hall ;  and  Catskill  group  of  Vanuxem. 

According  to  Hall  1843,  and  essentially  Vanuxem  1842. 

''  Chemung,  Portage  or  Nunda  (divided 
into  Cashaqua,  Gardeau,  Portage), 
Genesee,  Tully,  Hamilton  (divided 
into  Ludlowville,  Encrinal,  Moscow), 
and  Marcellus. 


Erie  division 
[Devonian] 


Helderberg  series 
[Devonian- 
Silurian] 

Ontario  division 
[Silurian] 

Champlain  division 
[  Silurian-Ordovi- 
cian-Upper 
Cambrian] 


''  Corniferous,  Onondaga,  Schoharie,  Cau- 
da-galli,  Oriskany,  Upper  Pentame- 
rus,  Encrinal,  Delthyris,  Pentamerus, 
Waterlime,  Onondaga  salt  group. 

Niagara,  Clinton,  and  Medina. 

Oneida  or  Shawangunk,  Grey  sandstone, 
Hudson  River  group,  Utica,  Trenton, 
Black  River  including  Birdseye  and 
Chazy,  Calciferous  sandrock,  and 
Potsdam. 


According  to  Emmons  1842,  Mather  1843,  Yanuxem  1842, 

Hall  1843. 

"^Tordovi^faTand     /  G^raiiular  quartz,  Stockbridge  limestone, 
Lower  Cambrian]  \      Magnesian  slate,  and  Taconic  slate. 


Primary  or  Hypo- 
gene  system 


Metamorphic  and  Primary  rocks. 


HISTORICAL  GEOLOGY  89 

aran,  while  the  Middle  Devonian  about  Columbus,  Ohio, 
and  Louisville,  Kentucky,  he  referred  to  the  same 
horizon.  The  Galena-Niagaran  error  was  corrected  in 
1855,  but  the  Devonian  and  Mississippian  ones  remained 
unadjusted  for  a  long  time,  and  in  Iowa  until  toward  the 
close  of  the  nineteenth  century. 

Correlations  tvith  Europe. — The  first  effort  toward 
correlating  the  New  York  system  with  those  of  Europe 
was  made  by  Conrad  in  his  Notes  on  American  Geology 
in  1839  (35,  243).  Here  he  compares  it  on  faunal 
grounds  with  the  Silurian  system.  A  more  sustained 
effort  was  that  of  Hall  in  1843  (45,  157),  when  he  said 
that  the  Silurian  of  Murchison  was  equal  to  the  New 
York  system  and  embraced  the  Cambrian,  Silurian,  and 
Devonian,  which  he  considered  as  forming  but  one  sys- 
tem. Hall  in  1844  and  Conrad  earlier  were  erroneously 
regarding  the  Middle  Devonian  of  New  York  (Hamilton) 
as  *^an  equivalent  of  the  Ludlow  rocks  of  Mr.  Murchi- 
son" (47,  118, 1844). 

In  1846  E.  P.  De  Verneuil  spent  the  summer  in  Amer- 
ica with  a  view  to  correlating  the  formations  of  the  New 
York  system  with  those  of  Europe.  At  this  time  he  had 
had  a  wide  field  experience  in  France,  Germany,  and 
Eussia,  was  president  of  the  Geological  Society  of 
France,  and  ^*  virtually  the  representative  of  European 
geology"  (2,  153,  1846).  Hall  says,  '*No  other  person 
could  have  presented  so  clear  and  perfect  a  coup  d'oeil." 
De  Verneuirs  results  were  translated  by  Hall  and  with 
his  own  comments  were  published  in  the  Journal  in  1848 
and  1849  under  the  title  *^0n  the  Parallelism  of  the 
Paleozoic  Deposits  of  North  America  with  those  of 
Europe."  De  Verneuil  was  especially  struck  with  the 
complete  development  of  American  Paleozoic  deposits 
and  said  it  was  the  best  anywhere.  On  the  other  hand, 
he  did  not  agree  with  the  detailed  arrangement  of  the 
formations  in  the  various  divisions  of  the  New  York 
system,  and  Hall  admitted  altogether  too  readily  that  the 
terms  were  proposed  *^as  a  matter  of  concession,  and  it  is 
to  be  regretted  that  such  an  artificial  classification  was 
adopted."    De  VerneuiPs  correlations  are  as  follows: 

The  Lower  Silurian  system  begins  with  the  Potsdam, 
the  analogue  of  the  Obolus  sandstone  of  Russia  and 


90  A  CENTURY  OF  SCIENCE 

Sweden.  The  Black  River  and  Trenton  hold  the  position 
of  the  Orthoceras  limestones  of  Sweden  and  Russia, 
while  the  Utica  and  Lorraine  are  represented  by  the 
Graptolite  beds  of  the  same  countries.  Both  correlations 
are  in  partial  error.  He  unites  the  Chazy,  Birdseye,  and 
Black  River  in  one  series,  and  in  another  the  Trenton, 
Utica,  and  Lorraine.  Of  species  common  to  Europe  and 
America  he  makes  out  seventeen. 

In  the  Upper  Silurian  system,  the  Oneida  and 
Shawangunk  are  taken  out  of  the  Champlain  division, 
and,  with  the  Medina,  are  referred  to  the  Silurian,  along 
with  all  of  the  Ontario  division  plus  the  Lower  Helder- 
berg.  The  Clinton  is  regarded  as  highest  Caradoc  or  as 
holding  a  stage  between  that  and  the  "Wenlock.  The 
Niagara  group  is  held  to  be  the  exact  equivalent  of  the 
Wenlock,  **  while  the  ^ve  inferior  groups  of  the  Helder- 
berg  division  represent  the  rocks  of  Ludlow."  We  now 
know  that  these  Helderberg  formations  are  Lower  Devo- 
nian in  age.  De  Verneuil  unites  in  one  series  the 
Waterlime,  Pentamerus,  Delthyris,  Encrinal,  and  Upper 
Pentamerus.  Of  identical  species  there  are  forty  com- 
mon to  Europe  and  America. 

The  Devonian  system  De  Verneuil  begins,  **  after 
much  hesitation,"  with  the  Oriskany  and  certainly  with 
the  five  upper  members  of  Hall 's  Helderberg  division,  all 
of  the  Erie  and  the  Old  Red  Sandstone.  He  also  adjusts 
HalPs  error  by  placing  in  the  Devonian  the  Upper  Cliff 
limestone  of  Ohio  and  Indiana,  regarded  by  the  former 
as  Silurian.  The  Oriskany  is  correlated  with  the  grau- 
wackes  of  the  Rhine,  and  the  Onondaga  or  Corniferous 
with  the  lower  Eifelian.  Cauda-galli,  Schoharie,^  and 
Onondaga  are  united  in  one  series ;  Marcellus,  Hamilton, 
TuUy,  and  Genesee  in  another;  and  Portage  and 
Chemung  in  a  third.  Of  species  common  to  Europe  and 
America  there  are  thirty-nine. 

The  Waverly  of  Ohio  and  that  near  Louisville,  Ken- 
tucky, which  Hall  had  called  Chemung,  De  Verneuil  cor- 
rectly refers  to  the  Carboniferous,  but  to  this  Hall  does 
not  consent.  De  Verneuil  points  out  that  there  are 
thirty-one  species  in  common  between  Europe  and  Amer- 
ica. **And  as  to  plants,  the  immense  quantity  of  terres- 
trial species  identical  on  the  two  sides  of  the  Atlantic, 


HISTORICAL  GEOLOGY  91 

proves  that  the  coal  was  formed  in  the  neighborhood  of 
lands  already  emerged,  and  placed  in  similar  physical 
conditions." 

An  analysis  of  the  Paleozoic  fossils  of  Europe  and 
America  leads  De  Verneuil  to  ^  ^  the  conviction  that  identi- 
cal species  have  lived  at  the  same  epoch  in  America  and 
in  Europe,  that  they  have  had  nearly  the  same  duration, 
and  that  they  succeeded  each  other  in  the  same  order.*' 
This  he  states  is  independent  of  the  depth  of  the  seas, 
and  of  *Hhe  upheavings  which  have  affected  the  surface 
of  the  globe.''  The  species  of  a  period  begin  and  drop 
out  at  different  levels,  and  toward  the  top  of  a  system 
the  whole  takes  on  the  character  of  the  next  one.  **If  it 
happens  that  in  the  two  countries  a  certain  number  of 
systems,  characterized  by  the  same  fossils,  are  superim- 
posed in  the  same  order,  whatever  may  be,  otherwise, 
their  thickness  and  the  number  of  physical  groups  of 
which  they  are  composed,  it  is  philosophical  to  consider 
these  systems  as  parallel  and  synchronous. ' ' 

Because  of  the  dominance  of  the  sandstones  and  shales 
in  eastern  New  York,  De  Verneuil  holds  that  a  land  lay 
to  the  east.  The  many  fucoids  and  ripple-marks  from 
the  Potsdam  to  the  Portage  indicated  to  him  shallow 
water  and  nearness  to  a  shore. 

The  Oldest  Geologic  Eras. — We  have  seen  in  previous 
pages  how  the  Primitive  rocks  of  Arduino  and  of  Werner 
had  been  resolved,  at  least  in  part,  into  the  systems  of 
the  Paleozoic,  but  there  still  remained  many  areas  of 
ancient  rocks  that  could  not  be  adjusted  into  the  accepted 
scheme.  One  of  the  most  extensive  of  these  is  in  Canada, 
where  the  really  Primitive  formations,  of  granites, 
gneisses,  schists,  and  even  undetermined  sediments, 
abound  and  are  developed  on  a  grander  scale  than  else- 
where, covering  more  than  two  million  square  miles  and 
overlain  unconf  ormably  by  the  Paleozoic  and  later  rocks. 
The  first  to  call  attention  to  them  was  J.  I.  Bigsby,  a 
medical  staff  officer  of  the  British  Army,  in  1821  (3, 
254).  It  was,  however,  William  E.  Logan  (1798-1875), 
the  '^father  of  Canadian  geology,"  who  first  unravelled 
their  historical  sequence.  At  first  he  also  called  them 
Primary,  but  after  much  work  he  perceived  in  them  par- 
allel structures  and  metamorphosed  sediments,  under- 


92  A  CENTURY  OF  SCIENCE 

lain  by  and  associated  with  pink  granites.  For  the 
oldest  masses,  essentially  the  granites,  he  proposed  the 
term  Laurentian  system  (1853,  1863)  and  for  the  altered 
and  deformed  strata,  the  name  Huronian  series  (1857, 
1863).  Overlying  these  unconformably  was  a  third 
series,  the  copper-bearing  rocks.  Since  his  day  a  great 
host  of  Canadian  and  American  geologists  have  labored 
over  this,  the  most  intricate  of  all  geology,  and  now  we 
have  the  following  tentative  chronology  (Schuchert  and 
Barrel!,  38,  1,  1914) : 

Late  Proterozoic  era. 

Keweenawan,  Animikian  and  Huronian  periods. 
Early  Proterozoic  era. 

Sudburian  period  or  older  Huronian. 
Archeozoic  era. 

Grenville  series,  etc. 
Cosmic  history. 

The  Taconic  Systeim  Resurrected, 

The  Taconic  system  was  first  announced  by  Ebenezer 
Emmons  in  1841,  and  clearly  defined  in  1842.  It  started 
the  most  bitter  and  most  protracted  discussion  in  the 
annals  of  American  geology.  After  Emmons  ^s  subse- 
quent publications  had  put  the  Taconic  system  through 
three  phases,  Barrande  of  Bohemia  in  1860-1863  shed  a 
great  deal  of  new  and  correct  light  upon  it,  affirming  in  a 
series  of  letters  to  Billings  that  the  Taconic  fossils  are 
like  those  of  his  Primordial  system,  or  what  we  now  call 
the  Middle  Cambrian  (31,  210,  1861,  et  seq.). 

In  a  series  of  articles  published  by  S.  W.  Ford  in  the 
Journal  between  1871  and  1886,  there  was  developed  the 
further  new  fact  that  in  Rensselaer  and  Columbia  coun- 
ties, New  York,  the  so-called  Hudson  River  group 
abounds  in  ^* Primordial"  fossils  wholly  unlike  those  of 
the  Potsdam,  and  which  Ford  later  on  spoke  of  as 
belonging  to  ^* Lower  Potsdam"  time. 

James  D.  Dana  entered  the  field  of  the  Taconic  area  in 
1871  and  demonstrated  that  the  system  also  abounds  in 
Ordovician  fossiliferous  formations.  Then  came  the 
far-reaching  work  of  Charles  D.  Walcott,  beginning  in 
1886,  which  showed  that  all  through  eastern  New  York 
and  into  northern  Vermont  the  Hudson  River  group  and 


HISTORICAL  GEOLOGY  93 

the  Taconic  system  abound  not  only  in  Ordovician  but 
also  in  Cambrian  fossils.  Finally  in  1888  Dana  pre- 
sented a  Brief  History  of  Taconic  Ideas,  aiid  laid  away 
the  system  with  these  words  (36,  27) : 

''It  is  almost  fifty  years  since  the  Taconic  system  made  its 
abrupt  entrance  into  geological  science.  Notwithstanding  some 
good  points,  it  has  been  through  its  greater  errors,  long  a  hin- 
drance to  progress  here  and  abroad  .  .  .  But,  whether  the  evil 
or  the  good  has  predominated,  we  may  now  hope,  while  heartily 
honoring  Professor  Emmons  for  his  earnest  geological  labors  and 
his  discoveries,  that  Taconic  ideas  may  be  allowed  to  be  and 
remain  part  of  the  past. ' ' 

As  an  epitaph  Dana  placed  over  the  remains  of  the 
Taconic  system  the  black-faced  numerals  1841-1888. 
That  the  remains  of  the  system,  however,  and  the  term 
Taconic  are  still  alive  and  demanding  a  rehearing  is 
apparent  to  all  interested  stratigraphers.  This  is  not 
the  place  to  set  the  matter  right,  and  all  that  can  be  done 
at  the  present  time  is  to  point  out  what  are  the  things 
that  still  keep  alive  Emmons's  system. 

In  the  typical  area  of  the  Taconic  system,  i.  e.,  in  Rens- 
selaer County,  Emmons  in  1844-1846  produced  the  fossils 
Atops  trilineatus  and  Elliptocephala  asaphoides.  S.  W. 
Ford,  as  stated  above,  later  produced  from  the  same  gen- 
eral area  many  other  fossils  that  he  demonstrated  to  be 
older  than  the  Potsdam  sandstone.  To  this  time  he  gave 
the  name  of  Lower  Potsdam,  thus  proving  on  paleon- 
tological  grounds  that  at  least  some  part  of  the  Taconic 
system  is  older  than  the  New  York  system,  and  therefore 
older  than  the  Hudson  River  group  of  Ordovician  age> 

In  1888  Walcott  presented  his  conclusions  in  regard  to 
the  sequence  of  the  strata  in  the  typical  Taconic  area  and 
to  the  north  and  south  of  it.  He  collected  Lower  Cam- 
brian fossils  at  more  than  one  hundred  localities 
*^ within  the  typical  Taconic  area,''  and  said  that  the 
thickness  of  his  ^^terrane  No.  5"  or  '^Cambrian  (Geor- 
gia)," now  referable  to  the  Lower  Cambrian,  is  **  14,000 
feet  or  more."  He  demonstrated  that  the  Lower  Cam- 
brian is  infolded  with  the  Lower  and  Middle  Ordovician, 
and  confirmed  Emmons 's  statement  that  the  former  rests 
upon  his  Primary  or  Pre-Cambrian  masses.  Elsewhere, 
he  writes:     ^'To  the  west  of  the  Taconic  range  the  sec- 


94  A  CENTURY  OF  SCIENCE 

tion  passes  down  through  the  limestone  (3)  [of  Lower 
and  Middle  Ordovician  age]  to  the  hydromica  schists  (2) 
[whose  age  may  also  be  of  early  Ordovician] ,  and  thence 
to  the  great  development  of  slates  and  shales  with  their 
interbedded  sparry  limestones,  calciferous  and  arenaceous 
strata,  all  of  which  contain  more  or  less  of  the  Olenellus 
.  .  .  fauna. ' '  He  then  knew  thirty-five  species  in  Wash- 
ington County,  New  York  (35,  401,  1888). 

Finally  in  1915  Walcott  said  that  in  the  Cordilleran 
area  of  America  there  was  a  movement  that  brought 
about  changes  *4n  the  sedimentation  and  succession  of 
the  faunas  which  serve  to  draw  a  boundary  line  between 
the  Lower  and  IMiddle  Cambrian  series.  .  .  .  The 
length  of  this  period  of  interruption  must  have  been  con- 
siderable .  .  .  and  when  connection  with  the  Pacific  was 
resumed  a  new  fauna  that  had  been  developing  in  the 
Pacific  was  then  introduced  into  the  Cordilleran  sea  and 
constituted  the  Middle  Cambrian  fauna.  The  change 
in  the  species  from  the  Lower  to  the  Middle  Cambrian 
fauna  is  very  great."  He  then  goes  on  to  show  that  in 
the  Appalachian  geosyncline  there  was  another  move- 
ment that  shut  out  the  Middle  Cambrian  Paradoxides 
fauna  of  the  Atlantic  realm  from  this  trough,  and  all 
deposition  as  well. 

Conclusions. — Accordingly  it  appears  that  everywhere 
in  America  the  Lower  Cambrian  formations  are  sep- 
arated by  a  land  interval  of  long  duration  from  those  of 
Middle  Cambrian  time.  These  formations  therefore 
unite  into  a  natural  system  of  rocks  or  a  period  of  time. 
Between  Middle  and  Upper  Cambrian  time,  however, 
there  appears  to  be  a  complete  transition  in  the  Cordil- 
leran trough,  binding  these  two  series  of  deposits  into 
one  natural  or  diastrophic  system.  Hence  the  writer 
proposes  that  the  Lower  Cambrian  of  America  be  known 
as  the  Taconic  system.  The  Middle  and  Upper  Cam- 
brian series  can  be  continued  for  the  present  under  the 
term  Cambrian  system,  a  term,  however,  that  is  by  no 
means  in  good  standing  for  these  formations,  as  will  be 
demonstrated  under  the  discussion  of  the  Silurian  con- 
troversy. 


HISTORICAL  GEOLOGY  95 

The  Silurian  Controversy, 

Just  as  in  America  the  base  of  the  Paleozoic  was 
involved  in  a  protracted  controversy,  so  in  England  the 
Cambrian-Silurian  succession  was  a  subject  of  long 
debate  between  Sedgwick  and  Murchison,  and  among  the 
succeeding  geologists  of  Europe.  The  history  of  the 
solution  is  so  well  and  justly  stated  in  the  Journal  by 
James  D.  Dana  under  the  title  **  Sedgwick  and  Murchi- 
son: Cambrian  and  Silurian''  (39,  167, 1890),  and  by  Sir 
Archibald  Geikie  in  his  Text-book  of  Geology,  1903,  that 
all  that  is  here  required  is  to  briefly  restate  it  and  to 
bring  the  solution  up  to  date. 

Adam  Sedgwick  (1785-1873)  and  R.  I.  Murchison 
(1792-1871)  each  began  to  work  in  the  areas  of  Cam- 
bria (Wales)  and  Siluria  (England)  in  1831,  but  the 
terms  Cambrian  and  Silurian  were  not  published  until 
1835.  Murchison  was  the  first  to  satisfactorily  work  out 
the  sequence  of  the  Silurian  system  because  of  the 
simpler  structural  and  more  fossiliferous  condition  of 
his  area.  Sedgwick,  on  the  other  hand,  had  his  academic 
duties  to  perform  at  Cambridge  University,  and  being  an 
older  and  more  conservative  man,  delayed  publishing  his 
final  results,  because  of  the  further  fact  that  his  area 
was  far  more  deformed  and  less  fossiliferous.  In  1834 
they  were  working  in  concert  in  the  Silurian  area,  and 
Sedgwick  said:  **I  was  so  struck  by  the  clearness  of  the 
natural  sections  and  the  perfection  of  his  workmanship 
that  I  received,  I  might  say,  with  implicit  faith  every- 
thing which  he  then  taught  me.  .  .  .  The  whole  '  Silurian 
system'  was  by  its  author  placed  above  the  great  undu- 
lating slate-rocks  of  South  Wales."  At  that  time  Mur- 
chison told  Sedgwick  that  the  Bala  group  of  the  latter, 
now  known  to  be  in  the  middle  of  the  Lower  Silurian, 
could  not  be  brought  within  the  limits  of  the  Silurian 
system,  and  added,  *  *  I  believe  it  to  plunge  under  the  true 
Llandeilo-flags, "  now  placed  next  below  the  Bala  and 
above  the  Arenig,  which  at  the  present  is  regarded  as  at 
the  base  of  the  Ordovician. 

The  Silurian  system  was  defined  in  print  by  Murchison 
in  July,  1835,  the  Upper  Silurian  embracing  the  Ludlow 
and  Wenlock,  while  the  Lower  Silurian  was  based  on  the 


96  A  CENTURY  OF  SCIENCE 

Caradoc  and  Llandeilo.  Murchison's  monumental  work, 
The  Silurian  System,  of  100  pages  and  many  plates  of 
fossils,  appeared  in  1838. 

The  Cambrian  system  was  described  for  the  first  time 
by  Sedgwick  in  August,  1835,  but  the  completed  work — a 
classic  in  geology — Synopsis  of  the  Classification  of  the 
British  Palaeozoic  Rocks,  along  with  M  'Coy's  Descriptions 
of  British  Palaeozoic  Fossils,  did  not  appear  until  1852- 
1855.  Sedgwick's  original  Upper  Cambrian  included  the 
greater  part  of  the  chain  of  the  Berwyns,  where  he  said 
it  was  connected  with  the  Llandeilo  flags  of  the  Silurian. 
The  Middle  Cambrian  comprised  the  higher  mountains  of 
Caernarvonshire  and  Merionethshire,  and  the  Lower 
Cambrian  was  said  to  occupy  the  southwest  coast  of 
Caernarvonshire,  and  to  consist  of  chlorite  and  mica 
schists,  and  some  serpentine  and  granular  limestone.  In 
1853  it  was  seen  that  the  fossiliferous  Upper  Cambrian 
included  the  Arenig,  Llandeilo,  Bala,  Caradoc,  Coniston, 
Hirnant,  and  Lower  Llandovery.  On  the  other  hand,  it 
was  not  until  long  after  Murchison  and  Sedgwick  passed 
away  that  the  Middle  and  Lower  Cambrian  were  shown 
to  have  fossils,  but  few  of  those  that  characterize  what 
is  now  called  Lower,  Middle,  and  Upper  Cambrian  time. 

Not  until  long  after  the  original  announcement  of  the 
Cambrian  system  did  Sedgwick  become  aware  **of  the 
unfortunate  mischief -involving  fact"  that  the  most  fos- 
siliferous portion  of  the  Cambrian — the  Upper  Cambrian 
— and  at  that  time  the  only  part  yielding  determinable 
fossils,  when  compared  with  the  Lower  Silurian  was 
seen  to  be  an  equivalent  formation  but  with  very  dif- 
ferent lithologic  conditions.  He  began  to  see  in  1842 
that  his  Cambrian  was  in  conflict  with  the  Silurian  sys- 
tem, and  four  years  later  there  were  serious  divergencies 
of  views  between  himself  and  Murchison.  The  climax 
of  the  controversy  was  attained  in  1852,  when  Sedgwick 
was  extending  his  Cambrian  system  upwards  to  include 
the  Bala,  Llandeilo,  and  Caradoc,  a  proceeding  not  unlike 
that  of  Murchison,  who  earlier  had  been  extending  his 
Silurian  downward  through  all  of  the  fossiliferous  Cam- 
brian to  the  base  of  the  LingTila  flags. 

Dana  in  his  review  of  the  Silurian- Cambrian  contro- 
versy states :  *  *  The  claim  of  a  worker  to  affix  a  name  to  a 


HISTORICAL  GEOLOGY  97 

series  of  rocks  first  studied  and  defined  by  him  cannot  be 
disputed.''  We  have  seen  that  Murchison  had  priority 
of  publication  in  his  term  Silurian  over  Sedgwick's  Cam- 
brian, but  that  in  a  complete  presentation,  both  strati- 
graphically  and  faunally,  the  former  had  years  of  prior 
definition.  What  has  even  more  weight  is  that  geologists 
nearly  everywhere  had  accepted  Murchison 's  Silurian 
system  as  founded  upon  the  Lower  and  Upper  Silurian 
formations.  A  nomenclature  once  widely  accepted  is 
almost  impossible  to  dislodge.  However,  in  regard  to 
the  controversy  it  should  not  be  forgotten  that  it  was 
only  Murchison 's  Loiver  Silurian  that  was  in  conflict 
with  Sedgwick's  Upper  Cambrian.  As  for  the  rest  of 
the  Cambrian,  that  was  not  involved  in  the  controversy, 

Dana  goes  on  to  state  that  science  may  accept  a  name, 
or  not,  according  as  it  is,  or  is  not,  needed.  In  the  prog- 
ress of  geology,  he  thought  that  the  time  had  finally  been 
reached  when  the  name  Cambrian  was  a  necessity,  and 
he  included  both  Cambrian  and  Silurian  in  the  geologi- 
cal record.  The  *  *  Silurian, ' '  however,  included  the  Lower 
and  Upper  Silurian — not  one  system  of  rocks,  but  two. 

It  is  now  twenty-seven  years  since  Dana  came  to  this 
conclusion,  at  a  time  when  it  was  believed  that  there  was 
more  or  less  continuous  deposition  not  only  between  the 
formations  of  a  system  but  between  the  systems  them- 
selves as  well.  To-day  many  geologists  hold  that  in  the 
course  of  time  the  oceans  pulsate  back  and  forth  over 
the  continents,  and  accordingly  that  the  sequence  of 
marine  sedimentation  in  most  places  must  be  much 
broken,  and  to-day  we  know  that  the  breaks  or  land  inter- 
vals in  the  marine  record  are  most  marked  between  the 
eras,  and  shorter  between  all  or  at  least  most  of  the 
periods.  Furthermore,  in  North  America,  we  have 
learned  that  the  breaks  between  the  systems  are  most 
marked  in  the  interior  of  the  continent  and  less  so  on  or 
toward  its  margins. 

Hardly  any  one  now  questions  the  fact  of  a  long  land 
interval  between  the  Lower  Silurian  and  Upper  Silurian 
in  England,  and  it  is  to  Sedgwick's  credit  that  he  was  the 
first  to  point  out  this  fact  and  also  the  presence  of  an 
unconformity.  It  therefore  follows  that  we  cannot  con- 
tinue to  use  Silurian  system  in  the  sense  proposed  by 


98  A  CENTURY  OF  SCIENCE 

Murchison,  since  it  includes  two  distinct  systems  or 
periods.  Dana,  in  the  last  edition  of  his  Manual  of 
Geology  (1895),  also  recognizes  two  systems,  but 
curiously  he  saw  nothing  incongruous  in  calling  them 
** Lower  Silurian  era''  and  ^^ Upper  Silurian  era.''  It 
certainly  is  not  conducive  to  clear  thinking,  however,  to 
refer  to  two  systems  by  the  one  name  of  Silurian  and  to 
speak  of  them  individually  as  Lower  and  Upper  Silurian, 
thus  giving  the  impression  that  the  two  systems  are  but 
parts  of  one — the  Silurian.  Each  one  of  the  parts  has  its 
independent  faunal  and  physical  characters. 

We  must  digress  a  little  here  and  note  the  work  of 
Joachim  Barrande  (1799-1883)  in  Bohemia.  In  1846  he 
published  a  short  account  of  the  *^ Silurian  system"  of 
Bohemia,  dividing  it  into  etages  lettered  C  to  H. 
Between  1852  and  1883  he  issued  his  ^ '  Systeme  Silurien 
du  Centre  de  la  Boheme,"  in  eighteen  quarto  volumes 
with  5568  pages  of  text  and  798  plates  of  fossils — a  mon- 
umental work  unrivalled  in  paleontology.  In  the  first 
volume  the  geology  of  Bohemia  is  set  forth,  and  here  we 
see  that  etages  A  and  B  are  Azoic  or  pre-Cambrian,  and 
C  to  H  make  up  his  Silurian  system.  Etage  C  has  his 
** Primordial  fauna,"  now  known  to  be  of  Paradoxides  or 
Middle  Cambrian  time,  while  D  is  Lower  Silurian,  E  is 
Upper  Silurian,  F  is  Lower  Devonian,  and  G  and  H  are 
Middle  Devonian.  From  this  it  appears  that  Barrande 's 
Silurian  system  is  far  more  extensive  than  that  of  Murchi- 
son, embracing  twice  as  many  periods  as  that  of  England 
and  Wales. 

About  1879  there  was  in  England  a  nearly  general 
agreement  that  Cambrian  should  embrace  Barrande 's 
Primordial  or  Paradoxides  faunas,  and  in  the  North 
Wales  area  be  continued  up  to  the  top  of  the  Tremadoc 
slates.  To-day  we  would  include  Middle  and  Upper 
Cambrian.  Lower  Cambrian  in  the  sense  of  containing 
the  Olenellus  faunas  was  then  unknown  in  Great  Britain. 

Lapworth,  recognizing  the  distinctness  of  the  Lower 
Silurian  as  a  system,  proposed  in  1879  to  reco,2:nize  it  as 
such,  and  named  it  Ordovician,  restricting  Silurian  to 
Murchison 's  Upper  Silurian.  This  term  has  not  been 
widely  used  either  in  Great  Britain  or  on  the  Continent, 
but  in  the  last  twenty  years  has  been  accepted  more  and 


HISTORICAL  GEOLOGY  99 

more  widely  in  America.  Even  here,  however,  it  is  in 
direct  conflict  with  the  term  Champlain,  proposed  by  the 
New  York  State  Geologist  in  1842. 

In  1897  the  International  Geological  Congress  pub- 
lished E.  Renevier^s  Chronographie  Geologique,  wherein 
we  find  the  following : 


.2 


Upper  or  Silurian        f  Ludlowian  (Murchison  1839). 

(Murchison,  re-       <   Wenlockian  (Murchison  1839). 
stricted,  1835).        |^  Landoverian  (Murchison). 
Middle  or  Ordovician  /  Caradocian  (Murchison  1839 ) . 

(Lapworth  1879).  {^^  IS^TlS' 
Lower  or  Cambrian     f  Potsdamian  (Emmons  1838). 

(Sedgwick,  re-         <  Menevian  (Salter  and  Hicks  1865), 

stricted,  1835).       |^  Georgian  (Hitchcock  1861). 


Eegarding  this  period,  which,  by  the  way,  is  not  very 
unlike  that  of  Barrande,  Renevier  remarks  that  it  is  ^*as 
important  as  the  Cretaceous  or  the  Jurassic.  Lapworth 
even  gives  it  a  value  of  the  first  order  equal  to  the  Pro- 
tozoic  era." 

In  the  above  there  is  an  obvious  objection  in  the  double 
usage  of  the  term  Silurian,  and  this  difficulty  was  met 
later  on  in  Lapparent's  Traite  by  the  proposal  to  substi- 
tute Gothlandian  for  Silurian.  Of  this  change  Geikie 
remarks:  ^^Such  an  arrangement  .  .  .  might  be  adopted 
if  it  did  not  involve  so  serious  an  alteration  of  the  nomen- 
clature in  general  use."  On  the  other  hand,  if  dias- 
trophism  and  breaks  in  the  stratigraphic  and  faunal 
sequence  are  to  be  the  basis  for  geologic  time  divisions, 
we  cannot  accept  the  above  scheme,  for  it  recognizes 
but  one  period  where  there  are  at  least  four  in  nature. 

Conclusions. — We  have  arrived  at  a  time  when  our 
knowledge  of  the  stratigraphic  and  faunal  sequence,  plus 
the  orogenic  record  as  recognized  in  the  principle  of 
diastrophism,  should  be  reflected  in  the  terminology  of 
the  geologic  time-table.  It  would  be  easy  to  offer  a  satis- 
factory nomenclature  if  we  were  not  bound  by  the  law  of 
priority  in  publication,  and  if  no  one  had  the  geologic 
chroliology  of  his  own  time  ingrained  in  his  memory. 
In  addition,  the  endless  literature,  with  its  accepted 
nomenclature,  bars  our  way.     Therefore  with  a  view  of 


100  A  CENTURY  OF  SCIENCE 

creating  the  least  change  in  geologic  nomenclature,  and 
of  doing  the  greatest  justice  to  our  predecessors  that  the 
present  conditions  of  our  knowledge  will  allow,  the  fol- 
lowing scheme  is  offered: 

Silurian  period.  Llandovery  to  top  of  Ludlow  in  Europe. 
Alexandrian-Cataract-Medina  to  top  of  Manlius  in  America. 

Champlain  (1842)  or  Ordovician  (1879)  period,  Arenig  to  top 
of  Caradoc  in  Europe.  Beekmantown  to  top  of  Richmondian 
in  America. 

Cambrian  period.  In  the  Atlantic  realm,  begins  with  the 
Paradoxides,  and  in  the  Pacific,  with  the  Bathyuriscus  and 
Ogygopsis  faunas.  The  close  is  involved  in  Ulrich's  provi- 
sionally defined  Ozarkian  system.  When  the  latter  is  estab- 
lished, the  Ozarkian  period  will  hold  the  time  between  the 
Ordovician  and  the  Cambrian. 

Taconic  period.  For  the  world-wide  Olenellus  or  Mesonacidae 
faunas. 

Paleogeography, 

When  geologists  began  to  perceive  the  vast  significance 
of  Hutton's  doctrine  that  *Hhe  ruins  of  an  earlier  world 
lie  beneath  the  secondary  strata/'  and  that  great  masses 
of  bedded  rocks  are  separated  from  one  another  by 
periods  of  mountain  making  and  by  erosion  intervals,  it 
was  natural  for  them  to  look  for  the  lands  that  had  fur- 
nished the  debris  of  the  accumulated  sediments.  In  this 
way  paleogeography  had  its  origin,  but  it  was  at  first  of 
a  descriptive  and  not  of  a  cartographic  nature. 

The  word  paleogeography  was  proposed  by  T.  Sterry 
Hunt  in  1872  in  a  paper  entitled  ^*The  Paleogeography 
of  the  North  American  Continent, ' '  and  published  in  the 
Journal  of  the  American  Geographical  Society  for  that 
year.  It  has  to  do,  he  says,  with  the  *' geographical  his- 
tory of  these  ancient  geological  periods.''  It  was  again 
prominently  used  by  Robert  Etheridge  in  his  presidential 
address  before  the  Geological  Society  of  London  in  1881. 
Since  Canu's  use  of  the  term  in  1896,  it  has  been  fre- 
quently seen  in  print,  and  now  is  generally  adopted  to 
signify  the  geography  of  geologic  time. 

The  French  were  the  first  to  make  paleogeographic 
maps,  and  Jules  Marcou  relates  in  1866  that  Elie  de 
Beaumont,  as  early  as  March,  1831,  in  his  course  in  the 
College  of  France  and  at  the  Paris  School  of  Mines,  used 


HISTORICAL  GEOLOGY  101 

to  outline  the  relation  of  the  lands  and  the  seas  in  the 
center  of  Europe  at  the  different  great  geologic  periods. 
His  first  printed  paleogeographic  map  appeared  in  1833, 
and  was  of  early  Tertiary  time.  Other  maps  by  Beau- 
mont were  published  by  Beudant  in  1841-1842.  The 
Sicilian  geologist  Gemmellaro  published  six  maps  of  his 
country  in  1834,  and  the  Englishman  De  La  Beche  had 
one  in  the  same  year.  In  America  the  first  to  show  such 
maps  was  Arnold  Guyot  in  his  Lowell  lectures  of  1848, 
James  D.  Dana  published  three  in  the  1863  edition  of  his 
Manual  of  Geology.  Of  world  paleogeographic  maps, 
Jules  Marcou  produced  the  first  of  Jurassic  time,  pub- 
lishing it  in  France  in  1866,  but  the  most  celebrated  of 
these  early  attempts  was  the  one  by  Neumayr  published 
in  1883  in  connection  with  his  Ueber  klimatische  Zonen 
wahrend  der  Jura-  und  Kreidezeit. 

The  first  geologist  to  produce  a  series  of  maps  showing 
the  progressive  geologic  geography  of  a  given  area  was 
Jukes-Brown,  who  in  the  volume  entitled  **The  Building 
of  the  British  Isles/'  1888,  included  fifteen  such  maps. 
Karpinsky  published  fourteen  maps  of  Russia,  and  in 
1896  Canu  in  his  Essai  de  paleogeographic  has  fifty-seven 
of  France  and  Belgium.  Lapparent's  Traite  of  1906  is 
famous  for  paleogeographic  maps,  for  he  has  twenty- 
three  of  the  world,  thirty-four  of  Europe,  twenty-five  of 
France,  and  ten  taken  from  other  authors.  Schuchert  in 
1910  published  fifty-two  to  illustrate  the  paleogeography 
of  North  America,  and  also  gave  an  extended  list  of  such 
published  maps.  Another  article  on  the  subject  is  by  Th. 
Arldt,  ^*Zur  Geschichte  der  Palaogeographischen  Rekon- 
structionen, "  published  in  1914.  Edgar  Dacque  in  1913 
also  produced  a  list  in  his  Palaogeographischen  Karten, 
and  two  years  later  appeared  his  book  of  500  pages, 
Grundlagen  und  Methoden  der  Palaogeographie,  where 
the  entire  subject  is  taken  up  in  detail. 

Conclusions. — Since  1833  there  have  been  published 
not  less  than  500  different  paleogeographic  maps,  and  of 
this  number  about  210  relate  to  North  America.  Never- 
theless paleogeography  is  still  in  its  infancy,  and  most 
maps  embrace  too  much  geologic  time,  all  of  them  tens 
of  thousands,  and  some  of  them  millions  of  years.  The 
geographic  maps  of  the  present  show  the  conditions  of 


102  A  CENTURY  OF  SCIENCE 

the  strand-lines  of  to-day,  and  those  made  fifty  years  ago 
have  to  be  revised  again  and  again  if  they  are  to  be  of 
value  to  the  mariner  and  merchant.  Therefore  in  our 
future  paleogeographic  maps  the  tendency  must  ever  be 
toward  smaller  amounts  of  geologic  time,  if  we  are  to 
show  the  actual  relation  of  water  to  land  and  the  move- 
ments of  the  periodic  floodings.  Moreover,  the  ancient 
shore  lines  are  all  more  or  less  hypothetic  and  are  drawn 
in  straight  or  sweeping  curves,  unlike  modern  strands 
with  their  bays,  deltas,  and  headlands,  and  the  ancient 
lands  are  featureless  plains.  We  must  also  pay  more 
attention  to  the  distribution  of  brackish-  and  fresh-water 
deposits.  The  periodically  rising  mountains  will  be  the 
first  topographic  features  to  be  shown  upon  the  ancient 
lands,  and  then  more  and  more  of  the  drainage  and  the 
general  climatic  conditions  must  be  portrayed.  In  the 
seas,  depth,  temperature,  and  currents  are  yet  to  be 
deciphered.  Finally,  other  base  maps  than  those  of  the 
geography  of  to-day  will  have  to  be  made,  allowing  for 
the  compression  of  the  mountainous  areas,  if  we  are  to 
show  the  true  geographic  configurations  of  the  lands  and 
seas  of  any  given  geologic  time. 

Paleometeorology, 

In  accordance  with  the  Laplacian  theory,  announced  at 
the  beginning  of  the  nineteenth  century,  all  of  the  older 
geologists  held  that  the  earth  began  as  a  hot  star,  and 
that  in  the  course  of  time  it  slowly  cooled  and  finally 
attained  its  present  zonal  cold  to  tropical  climatic  condi- 
tions. That  the  earth  had  very  recently  passed  through 
a  much  colder  climate,  a  glacial  one,  came  into  general 
acceptance  only  during  the  latter  half  of  the  previous 
century. 

Rise. — Our  knowledge  of  glacial  climates  had  its  origin 
in  the  Alps,  that  wonderland  of  mountains  and  glaciers. 
The  rise  of  this  knowledge  in  the  Alps  is  told  in  a  charm- 
ing and  detailed  manner  by  that  erratic  French- 
American  geologist,  Jules  Marcou  (1824-1898),  in  his 
Life,  Letters,  and  Works  of  Louis  Agassiz,  1896.  He 
relates  that  the  Alpine  chamois  hunter  Perraudin  in  1815 
directed  the  attention  of  the  engineer  De  Charpentier  to 
the  fact  *Hhat  the  large  boulders  perched  on  the  sides  of 


HISTORICAL  GEOLOGY  103 

the  Alpine  valleys  were  carried  and  left  there  by  gla- 
ciers.''  For  a  long  time  the  latter  thought  the  conclusion 
extravagant,  and  in  the  meantime  Perraudin  told  the 
same  thing  to  another  engineer,  Venetz.  He,  in  1829, 
convinced  of  the  correctness  of  the  chamois  hunter's 
views,  presented  the  matter  before  the  Swiss  naturalists 
then  meeting  at  St.  Bernard's.  Venetz  'Hold  the  Society 
that  his  observations  led  him  to  believe  that  the  whole 
Valais  has  been  formerly  covered  by  an  immense  glacier 
and  that  it  even  extended  outside  of  the  canton,  covering 
all  the  Canton  de  Vaud,  as  far  as  the  Jura  Mountains, 
carrying  the  boulders  and  erratic  materials,  which  are 
now  scattered  all  over  the  large  Swiss  valley."  Eight 
years  earlier,  in  1821,  similar  views  had  been  presented 
by  the  same  modest  naturalist  before  the  Helvetic 
Society,  but  it  was  not  until  1833  that  De  Charpentier 
found  the  manuscript  and  had  it  published.  Venetz 's 
conclusions  were  that  all  of  the  glaciers  of  the  Bagnes 
valley  ''have  very  recognizable  moraines,  which  are 
about  a  league  from  the  present  ice.''  "The  moraines 
.  .  .  date  from  an  epoch  which  is  lost  in  the  night  of 
time."  Then  in  1834  De  Charpentier  read  a  paper 
before  the  same  society,  meeting  at  Lucerne.  "Seldom, 
if  ever,  has  such  a  small  memoir  so  deeply  excited  the 
scientific  world.  It  was  received  at  first  with  incredulity 
and  even  scorn  and  mockery,  Agassiz  being  among  its 
opponents."  The  paper  was  published  in  1835,  first  at 
Paris,  then  at  Geneva,  and  finally  in  Germany.  It 
"attracted  much  attention,  and  the  smile  of  incredulity 
with  which  it  was  received  when  read  at  Lucerne  soon 
changed  into  a  desire  to  know  more  about  it." 

Louis  Agassiz  (1807-1873),  who  had  long  been  ac- 
quainted with  his  countryman,  De  Charpentier,  spent 
several  months  with  him  in  1836,  and  together  they 
studied  the  glaciers  of  the  Alps.  Agassiz  was  at  first 
"adverse  to  the  hypothesis,  and  did  not  believe  in  the 
great  extension  of  glaciers  and  their  transportation  of 
boulders,  but  on  the  contrary,  was  a  partisan  of  Lyell's 
theory  of  transport  by  icebergs  and  ice-cakes  .  .  .  but 
from  being  an  adversary  of  the  glacial  theory,  he 
returned  to  Neuchatel  an  enthusiastic  convert  to  the 
views    of   Venetz   and   De    Charpentier.  .  .  .  With   his 


104  A  CENTURY  OF  SCIENCE 

power  of  quick  perception,  his  unmatched  memory,  his 
perspicacity  and  acuteness,  his  way  of  classifying,  judg- 
ing and  marshalling  facts,  Agassiz  promptly  learned  the 
whole  mass  of  irresistible  arguments  collected  patiently 
during  seven  years  by  De  Charpentier  and  Venetz,  and 
with  his  insatiable  appetite  and  that  faculty  of  assimila- 
tion which  he  possessed  in  such  a  wonderful  degree,  he 
digested  the  whole  doctrine  of  the  glaciers  in  a  few 
weeks. ' ' 

In  July,  1837,  Agassiz  presented  as  his  presidential 
address  before  the  Helvetic  Society  his  memorable  ^*Dis- 
cours  de  Neuchatel,'^  which  was  **the  starting  point  of 
all  that  has  been  written  on  the  Ice-age,  '^ — a  term  coined 
at  the  time  by  his  friend  Schimper,  a  botanist.  The  first 
part  of  this  address  is  reprinted  in  French  in  Marcou's 
book  on  Agassiz.  The  address  was  received  with  aston- 
ishment, much  incredulity,  and  indifference.  Among  the 
listeners  was  the  great  German  geologist  Von  Buch,  who 
*^was  horrified,  and  with  his  hands  raised  towards  the 
sky,  and  his  head  bowed  to  the  distant  Bernese  Alps, 
exclaimed:  ^0  Sancte  de  Saussure,  ora  pro  nobis!'  '' 
Even  De  Charpentier  *^was  not  gratified  to  see  his  glacial 
theory  mixed  with  rather  uncalled  for  biological  prob- 
lems, the  connection  of  which  with  the  glacial  age  was 
more  than  problematic. ' '  Agassiz  was  then  a  Cuvierian 
catastrophist  and  creationist,  and  advanced  the  idea  of 
a  series  of  glacial  ages  to  explain  the  destruction  of  the 
geologic  succession  of  faunas!  Curiously,  this  theory 
was  at  once  accepted  by  the  American  paleontologist 
T.  A.  Conrad  (35,  239,  1839). 

The  classics  in  glacial  geology  are  Agassiz 's  Etudes 
sur  les  Glaciers,  1840,  and  De  Charpentier 's  Essai  sur  les 
Glaciers,  1841.  Of  the  latter  book,  Marcou  states  that 
it  has  been  said:  **It  is  impossible  to  be  truly  a  geologist 
without  having  read  and  studied  it."  In  the  English 
language  there  is  TyndalPs  Glaciers  of  the  Alps,  1860. 

The  progress  of  the  ideas  in  regard  to  Pleistocene 
glaciation  is  presented  in  the  following  chapter  by  H.  E. 
Gregory. 

Older  Glacial  Climates. — Hardly  had  the  Pleistocene 
glacial  climate  been  proved,  when  geologists  began  to 
point  out  the  possibility  of  even  earlier  ones.     An  enthu- 


HISTORICAL  GEOLOGY  105 

siastic  Scotch  writer,  Sir  Andrew  Eamsay,  in  1855 
described  certain  late  Paleozoic  conglomerates  of  middle 
England,  which  he  said  were  of  glacial  origin,  but  his 
evidence,  though  never  completely  gainsaid,  has  not  been 
generally  accepted.  In  the  following  year,  an  English- 
man, Doctor  W.  T.  Blanford,  said  that  the  Talchir  con- 
glomerates of  central  and  southern  India  were  of  glacial 
origin,  and  since  then  the  evidence  for  a  Permian  glacial 
climate  has  been  steadily  accumulating.  Africa  is  the 
land  of  tillites,  and  here  in  1870  Sutherland  pointed  out 
that  the  conglomerates  of  the  Karroo  formation  were  of 
glacial  origin.  Australia  also  has  Permian  glacial 
deposits,  and  they  are  known  widely  in  eastern  Brazil, 
the  Falkland  Islands,  the  vicinity  of  Boston,  and  else- 
where. So  convincing  is  this  testimony  that  all  geolo- 
gists are  now  ready  to  accept  the  conclusion  that  a 
glacial  climate  was  as  wide-spread  in  early  Permian  time 
as  was  that  of  the  Pleistocene.^ 

In  South  Africa,  beneath  the  marine  Lower  Devonian, 
occurs  the  Table  Mountain  series,  5000  feet  thick.  The 
series  is  essentially  one  of  quartzites,  with  zones  of  shales 
or  slates  and  with  striated  pebbles  up  to  15  inches  long. 
The  latter  occur  in  pockets  and  seem  to  be  of  glacial  origin. 
There  are  here  no  typical  tillites,  and  no  striated  under- 
grounds have  so  far  been  found.  While  the  evidence  of 
the  deposits  appears  to  favor  the  conclusion  that  the 
Table  Mountain  strata  were  laid  down  in  cold  waters  with 
floating  ice  derived  from  glaciers,  it  is  as  yet  impossible 
to  assign  these  sediments  a  definite  geologic  age.  They 
are  certainly  not  younger  than  the  Lower  Devonian,  but 
it  has  not  yet  been  established  to  what  period  of  the 
early  Paleozoic  they  belong. 

In  southeastern  Australia  occur  tillites  of  wide  distri- 
bution that  lie  conformably  beneath,  but  sharply  sep- 
arated from  the  fossiliferous  marine  Lower  Cambrian 
strata.  David  (1907),  Howchin  (1908),  and  other  Aus- 
tralian geologists  think  they  are  of  Cambrian  time,  but 
to  the  writer  they  seem  more  probably  late  Proterozoic 
in  age.  In  arctic  Norway  Reusch  discovered  unmistak- 
able tillites  in  1891,  and  this  occurrence  was  confirmed  by 
Strahan  in  1897.  It  is  not  yet  certainly  known  what 
their  age  is,  but  it  appears  to  be  late  Proterozoic  rather 


106  A  CENTURY  OF  SCIENCE 

than  early  Paleozoic.  Other  undated  Proterozoic  tillites 
occur  in  China  (Willis  and  Blackwelder  1907),  Africa 
(Schwarz  1906),  India  (Vredenburg  1907),  Canada 
(Coleman  1908),  and  possibly  in  Scotland. 

The  oldest  known  tillites  are  described  by  Coleman  in 
1907,  and  occur  at  the  base  of  the  Lower  Huronian  or  in 
early  Proterozoic  time.  They  extend  across  northern 
Ontario  for  1000  miles,  and  from  the  north  shore  of  Lake 
Huron  northward  for  750  miles. 

Fossils  as  Climatic  Indexes. — Paleontologists  have 
long  been  aware  that  variations  in  the  climates  of  the 
past  are  indicated  by  the  fossils,  and  Neumayr  in  1883 
brought  the  evidence  together  in  his  study  of  climatic 
zones  mentioned  elsewhere.  Plants,  and  corals,  cepha- 
lopods,  and  foraminifers  among  marine  animals,  have 
long  been  recognized  as  particularly  good  *4ife  ther- 
mometers." In  fact,  all  fossils  are  climatic  indicators 
to  some  extent,  and  a  good  deal  of  evidence  concerning 
paleometeorology  has  been  discerned  in  them.  This  evi- 
dence is  briefly  stated  in  the  paper  by  Schuchert  already 
alluded  to,  and  in  W.  D.  Matthew's  Climate  and  Evolu- 
tion, 1915. 

Sediments  as  Climatic  Indexes. — Johannes  Walther  in 
the  third  part  of  his  Einleitung — Lithogenesis  der 
Gegenwart,  1894 — is  the  first  one  to  decidedly  direct 
attention  to  the  fact  that  the  sediments  also  have  within 
themselves  a  climatic  record.  In  America  Joseph  Bar- 
rell  has  since  1907  written  much  on  the  same  subject. 
On  the  other  hand,  the  periodic  floodings  of  the  con- 
tinents by  the  oceans,  and  the  making  of  mountains, 
due  to  the  periodic  shrinkage  of  the  earth,  as  expressed 
in  T.  C.  Chamberlin's  principle  of  diastrophism  and  in 
his  publications  since  1897,  are  other  criteria  for  estimat- 
ing the  climates  of  the  past. 

Conclusions. — In  summation  of  this  subject  Schuchert 
says: 

**The  marine  'life  thermometer'  indicates  vast  stretches  of 
time  of  mild  to  warm  and  equable  temperatures,  with  but  slight 
zonal  differences  between  the  equator  and  the  poles.  The  great 
bulk  of  marine  fossils  are  those  of  the  shallow  seas,  and  the  evo- 
lutionary changes  recorded  in  these  'medals  of  creation'  are 
slight  throughout  vast  lengths  of  time  that  are  punctuated  by 


HISTORICAL  GEOLOGY  107 

short  but  decisive  periods  of  cooled  waters  and  great  mortality, 
followed  by  quick  evolution,  and  the  rise  of  new  stocks.  The 
times  of  less  warmth  are  the  miotherm  and  those  of  greater 
heat  the  pliotherm  periods  of  Eamsay. 

On  the  land  the  story  of  the  climatic  changes  is  different,  but 
in  general  the  equability  of  the  temperature  simulates  that  of 
the  oceanic  areas.  In  other  words,  the  lands  also  had  long- 
enduring  times  of  mild  to  warm  climates.  Into  the  problem 
of  land  climates,  however,  enter  other  factors  that  are  absent 
in  the  oceanic  regions,  and  these  have  great  influence  upon  the 
climates  of  the  continents.  Most  important  of  these  is  the  peri- 
odic  warm-water  inundation  of  the  continents  by  the  oceans, 
causing  insular  climates  that  are  milder  and  moister.  With  the 
vanishing  of  the  floods  somewhat  cooler  and  certainly  drier 
climates  are  produced.  The  effects  of  these  periodic  floods  must 
not  be  underestimated,  for  the  North  American  continent  was 
variably  submerged  at  least  seventeen  times,  and  over  an  area 
of  from  154.000  to  4,000,000  square  miles. 

When  to  these  factors  is  added  the  effect  upon  the  climate 
caused  by  the  periodic  rising  of  mountain  chains,  it  is  at  once 
apparent  that  the  lands  must  have  had  constantly  varying 
climates.  In  general  the  temperature  fluctuations  seem  to  have 
been  slight,  but  geographically  the  climates  varied  between  mild 
to  warm  pluvial,  and  mild  to  cool  arid.  The  arid  factor  has 
been  of  the  greatest  import  to  the  organic  world  of  the  lands. 
Further,  when  to  all  of  these  causes  is  added  the  fact  that  dur- 
ing emergent  periods  the  formerly  isolated  lands  were  connected 
by  land  bridges,  permitting  intermigration  of  the  land  floras 
and  faunas,  with  the  introduction  of  their  parasites  and  parasitic 
diseases,  we  learn  that  while  the  climatic  environment  is  of  fun- 
damental importance  it  is  not  the  only  cause  for  the  more  rapid 
evolution  of  terrestrial  life    .    .    . 

Briefly,  then,  we  may  conclude  that  the  markedly  varying 
climates  of  the  past  seem  to  be  due  primarily  to  periodic  changes 
in  the  topographic  form  of  the  earth's  surface,  plus  variations 
in  the  amount  of  heat  stored  by  the  oceans.  The  causation  for 
the  warmer  interglacial  climates  is  the  most  difficult  of  all  to 
explain,  and  it  is  here  that  factors  other  than  those  mentioned 
may  enter. 

Granting  all  this,  there  still  seems  to  lie  back  of  all  these 
theories  a  greater  question  connected  with  the  major  changes  in 
paleometeorology.  This  is:  What  is  it  that  forces  the  earth's 
topography  to  change  with  varying  intensity  at  irregularly 
rhythmic  intervals  ?  .  .  .  Are  we  not  forced  to  conclude  that 
the  earth's  shape  changes  periodically  in  response  to  gravitative 
forces  that  alter  the  body-form?" 


108  A  CENTURY  OF  SCIENCE 

Evolution. 

Modern  evolution,  or  the  theory  of  life  continuously 
descending  from  life  with  change,  may  be  said  to  have 
had  its  first  marked  development  in  Comte  de  Buffon 
(1707-1788),  a  man  of  wealth  and  station,  yet  an  indus- 
trious compiler,  a  brilliant  writer,  and  a  popularizer  of 
science.  He  was  not,  however,  a  true  scientific  investi- 
gator, and  his  monument  to  fame  is  his  Histoire  Nat- 
urelle,  in  forty-four  volumes,  1749-1804.  A.  S.  Packard 
in  his  book  on  Lamarck,  his  Life  and  Work,  1901,  con- 
cludes in  regard  to  Buff  on  as  follows : 

'*The  impression  left  on  the  mind,  after  reading  Buff  on,  is 
that  even  if  he  threw  out  these  suggestions  and  then  retracted 
them,  from  fear  of  annoyance  or  even  persecution  from  the 
bigots  oi  his  time,  he  did  not  himself  always  take  them  seriously, 
but  rather  jotted  them  down  as  passing  thoughts  .  .  .  They 
appeared  thirty-four  years  before  Lamarck's  theory,  and  though 
not  epoch-making,  they  are  such  as  will  render  the  name  of 
Buff  on  memorable  for  all  time.'* 

Chevalier  de  Lamarck  (1744-1829)  may  justly  be 
regarded  as  the  founder  of  the  doctrine  of  modern  evo- 
lution. Previous  to  1794  he  was  a  believer  in  the  fixity 
of  species,  but  by  1800  he  stood  definitely  in  favor  of 
evolution.  Locy  in  his  Biology  and  its  Makers,  1908, 
states  his  theories  in  the  following  simplified  form : 

'*  Variations  of  organs,  according  to  Lamarck,  arise  in  animals 
mainly  through  use  and  disuse,  and  new  organs  have  their  origin 
in  a  physiological  need.  A  new  need  felt  by  the  animal  [due 
to  new  conditions  in  its  life,  or  the  environment]  expresses 
itself  on  the  organism,  stimulating  growth  and  adaptations  in  a 
particular  direction.  * ' 

To  Lamarck,  'inheritance  was  a  simple,  direct  trans- 
mission of  those  superficial  changes  that  arise  in  organs 
within  the  lifetime  of  an  individual  owing  to  use  and 
disuse. '*  This  part  of  his  theory  has  come  to  be  known 
as  **the  inheritance  of  acquired  characters." 

Georges  Cuvier  (1769-1832),  a  peer  of  France,  was  a 
decided  believer  in  the  fixity  of  species  and  in  their  crea- 
tion through  divine  acts.  In  1796  he  began  to  see  that 
among  the  fossils  so  plentiful  about  Paris  many  were  of 


HISTORICAL  GEOLOGY  109 

extinct  forms,  and  later  on  that  there  was  a  succession 
of  wholly  extinct  faunas.  This  at  first  puzzling  phenom- 
enon he  finally  came  to  explain  by  assuming  that  the 
earth  had  gone  through  a  series  of  catastrophes,  of  which 
the  Deluge  was  the  most  recent  but  possibly  not  the  last. 
With  each  catastrophe  all  life  was  blotted  out,  and  a  new 
though  improved  set  of  organisms  was  created  by  divine 
acts.  The  Cuvierian  theory  of  catastrophism  was  widely 
accepted  during  the  first  half  of  the  nineteenth  century, 
and  in  America  Louis  Agassiz  was  long  its  greatest 
exponent.  It  was  this  theory  and  the  dominance  of  the 
brilliant  Cuvier,  not  only  in  science  but  socially  as  well, 
that  blotted  out  the.  far  more  correct  views  of  the  more 
philosophical  Lamarck,  who  held  that  life  throughout  the 
ages  had  been  continuous  and  that  through  individual 
effort  and  the  inheritance  of  acquired  characters  had 
evolved  the  wonderful  diversity  of  the  present  living 
world. 

In  1830  there  was  a  public  debate  at  Paris  between 
Cuvier  and  Geoffroy  Saint-Hilaire,  the  one  holding  to  the 
views  of  the  fixity  of  species  and  creation,  the  other  that 
life  is  continuous  and  evolves  into  better  adapted  forms. 
Cuvier,  a  gifted  speaker  and  the  greatest  debater  zoology 
ever  had,  with  an  extraordinary  memory  that  never 
failed  him,  defeated  Saint-Hilaire  in  each  day's  debate, 
although  the  latter  was  in  the  right. 

A  book  that  did  a  great  deal  to  prepare  the  English- 
speaking  people  for  the  coming  of  evolution  was  **  Ves- 
tiges of  Creation,"  published  in  1844  by  an  unknown 
author.  In  Darwin's  opinion,  *Hhe  work,  from  its  power- 
ful and  brilliant  style  .  .  .  has  done  excellent  service 
...  in  thus  preparing  the  ground  for  the  reception  of 
analogous  views."  This  book  was  recommended  to  the 
readers  of  the  Journal  (48,  395,  1845)  with  the  editorial 
remark  that  **we  cannot  subscribe  to  all  of  the  author's 
views." 

We  can  probably  best  illustrate  the  opinions  of  Amer- 
icans on  the  question  of  evolution  just  before  the  appear- 
ance of  Darwin's  great  work  by  directing  attention  to 
James  D.  Dana's  Thoughts  on  Species  (24,  305,  1857). 
After  reading  this  article  and  others  of  a  similar  nature 
by  Agassiz,  one  comes  to  the  opinion  that  unconsciously 


110  A  CENTURY  OF  SCIENCE 

both  men  are  proving  evolution,  but  consciously  they 
are  firm  creationists.  It  is  astonishing  that  with  their 
extended  and  minute  knowledge  of  living  organisms  and 
their  philosophic  type  of  mind  neither  could  see  the  true 
significance  of  the  imperceptible  transitions  between 
some  species,  which  if  they  do  not  actually  pass  into,  at 
least  shade  towards,  one  another. 

Dana  speaks  of  *^the  endless  diversities  in  individu- 
als ' '  that  compose  a  species,  and  then  states  that  a  living 
species,  like  an  inorganic  one,  *'is  based  on  a  specific 
amount  or  condition  of  concentered  force  defined  in  the 
act  or  law  of  creation.'^  Species,  he  says,  are  perma- 
nent, and  hybrids  *^  cannot  seriously  trifle  with  the  true 
units  of  nature,  and  at  the  best,  can  only  make  tempo- 
rary variations.''  **"We  have  therefore  reason  to  believe 
from  man's  fertile  intermixture,  that  he  is  one  in  species : 
and  that  all  organic  species  are  divine  appointments 
which  cannot  be  obliterated,  unless  by  annihilating  the 
individuals  representing  the  species." 

Through  the  activities  of  the  French  the  world  was 
prepared  for  the  reception  of  evolution,  and  now  it  was 
already  in  the  minds  of  many  advanced  thinkers.  In 
1860  Asa  Gray  sent  to  the  editor  of  the  Journal  (29,  1) 
an  article  by  the  English  botanist,  Joseph  D.  Hooker, 
entitled  **0n  the  Origination  and  Distribution  of 
Species,"  with  these  significant  remarks : 

' '  The  essay  cannot  fail  to  attract  the  immediate  and  profound 
attention  of  scientific  men  ...  It  has  for  some  time  been 
manifest  that  a  re-statement  of  the  Lamarckian  hypothesis  is 
at  hand.  We  have  this,  in  an  improved  and  truly  scientific 
form,  in  the  theories  v^^hich,  recently  propounded  by  Mr.  Dar- 
win, followed  by  Mr.  "Wallace,  are  here  so  ably  and  altogether 
independently  maintained.  When  these  views  are  fully  laid 
before  them,  the  naturalists  of  this  country  will  be  able  to 
take  part  in  the  interesting  discussion  which  they  will  not  fail 
to  call  forth.'* 

Hooker  took  up  a  study  of  the  flora  of  Tasmania,  of 
which  the  above  cited  article  is  but  a  chapter,  with  a 
view  to  trying  out  Darwin's  theory,  and  he  now  accepts 
it.  He  says,  ** Species  are  derivative  and  mutable." 
**The  limits  of  the  majority  of  species  are  so  undefina- 
ble  that  few  naturalists  are  agreed  upon  them." 


HISTORICAL  GEOLOGY  111 

Asa  Gray  had  received  from  Darwin  an  advance  copy 
of  the  book  that  was  to  revolutionize  the  thought  of  the 
world,  and  at  once  wrote  for  the  Journal  a  Review  of 
Darwin's  Theory  on  the  Origin  of  Species  by  means  of 
Natural  Selection  (29,  153,  1860).  This  is  a  splendid, 
critical  but  just,  scientific  review  of  Darwin's  epoch- 
making  book.  Evidently  views  similar  to  those,  of  the 
English  scientist  had  long  been  in  the  mind  of  Gray,  for 
he  easily  and  quickly  mastered  the  work.  He  is  easy  on 
Dana's  Thoughts  on  Species,  which  were  idealistic  and 
not  in  harmony  with  the  naturalistic  views  of  Darwin. 
On  the  other  hand,  he  contrasts  Darwin's  views  at  length 
with  those  of  the  creationists  as  exemplified  by  Louis 
Agassiz,  and  says  *^The  widest  divergence  appears." 

Gray  says  in  part : 

''The  gist  of  Mr.  Darwin's  work  is  to  show  that  such  varieties 
are  gradually  diverged  into  species  and  genera  through  natural 
selection;  that  natural  selection  is  the  inevitable  result  of  the 
struggle  for  existence  which  all  living  things  are  engaged  in; 
and  'that  this  struggle  is  an  unavoidable  consequence  of  several 
natural  causes,  but  mainly  of  the  high  rate  at  which  all  organic 
beings  tend  to  increase. 

Darwin  is  confident  that  intermediate  forms  must  have 
existed;  that  in  the  olden  times  when  the  genera,  the  families 
and  the  orders  diverged  from  their  parent  stocks,  gradations 
existed  as  fine  as  those  which  now  connect  closely  related  species 
with  varieties.  But  they  have  passed  and  left  no  sign.  The 
geological  record,  even  if  all  displayed  to  view,  is  a  book  from 
which  not  only  many  pages,  but  even  whole  alternate  chapters 
have  been  lost  out,  or  rather  which  were  never  printed  from  the 
autographs  of  nature.  The  record  was  actually  made  in  fossil 
lithography  only  at  certain  times  and  under  certain  conditions 
(i.  e.,  at  periods  of  slow  subsidence  and  places  of  abundant  sedi- 
ment) ;  and  of  these  records  all  but  the  last  volume  is  out  of 
print;  and  of  its  pages  only  local  glimpses  have  been  obtained. 
Geologists,  except  Lyell,  will  object  to  this, — some  of  them 
moderately,  others  with  vehemence.  Mr.  Darwin  himself  admits, 
with  a  candor  rarely  displayed  on  such  occasions,  that  he  should 
have  expected  more  geological  evidence  of  transition  than  he 
finds,  and  that  all  the  most  eminent  paleontologists  maintain  the 
immutability  of  species. 

The  general  fact,  however,  that  the  fossil  fauna  of  each  period 
as  a  whole  is  nearly  intermediate  in  character  between  the 
preceding  and  the  succeeding  faunas,  is  much  relied  on.     We 


112  A  CENTURY  OF  SCIENCE 

are  brought  one  step  nearer  to  the  desired  inference  by  the  similar 
'fact,'  insisted  on  by  all  paleontologists,  that  fossils  from  two 
consecutive  formations  are  far  more  closely  related  to  each  other, 
than  are  the  fossils  of  two  remote  formations. 

It  is  well  said  that  all  organic  beings  have  been  formed  on  two 
great  laws ;  Unity  of  type,  and  Adaptation  to  the  conditions  of 
existence  .  .  .  Mr.  Darwin  harmonizes  and  explains  them 
naturally.  Adaptation  to  the  conditions  of  existence  is  the 
result  of  Natural  Selection;  Unity  of  type,  of  unity  of  descent." 

Gray's  article  was  soon  followed  by  another  one  from 
Agassiz  on  Individuality  and  Specific  Differences  among 
Acalephs,  but  the  running  title  is  ^'Prof.  Agassiz  on  the 
Origin  of  Species''  (30,  142,  1860).  Agassiz  stoutly 
maintains  his  well  known  views,  and  concludes  as 
follows : 

''Were  the  transmutation  theory  true,  the  geological  record 
should  exhibit  an  uninterrupted  succession  of  types  blending 
gradually  into  one  another.  The  fact  is  that  throughout  all 
geological  times  each  period  is  characterized  by  definite  specific 
types,  belonging  to  definite  genera,  and  these  to  definite  families, 
referable  to  definite  orders,  constituting  definite  classes  and 
definite  branches,  built  upon  definite  plans.  Until  the  facts  of 
Nature  are  shown  to  have  been  mistaken  by  those  who  have  col- 
lected them,  and  that  they  have  a  different  meaning  from  that 
now  generally  assigned  to  them,  I  shall  therefore  consider  the 
transmutation  theory  as  a  scientific  mistake,  untrue  in  its  facts, 
unscientific  in  its  method,  and  mischievous  in  its  tendency." 

Dana,  in  reviewing  Huxley's  well  known  book,  Man's 
Place  in  Nature  (35,  451,  1863),  holds  that  man  is  apart 
from  brute  nature  because  man  exhibits  '*  extreme  ceph- 
alization"  in  that  he  has  arms  that  no  longer  are  used 
in  locomotion  but  go  rather  with  the  head,  and  because 
he  has  a  far  higher  mentality  and  speech.  As  for  the 
Darwinian  theory,  the  evidence,  he  says,  ^' comes  from 
lower  departments  of  life,  and  is  acknowledged  by  its 
advocates  to  be  exceedingly  scanty  and  imperfect." 

The  growth  of  evolution  is  set  forth  in  the  Journal  in 
Asa  Gray's  article  on  Charles  Darwin  (24,  453,  1882), 
which  speaks  of  the  latter  as  ^^the  most  celebrated  man  of 
science  of  the  nineteenth  century,"  and,  in  addition,  as 
**one  of  the  most  kindly  and  charming,  unaffected,  sim- 
ple-hearted, and  lovable  of  men. ' '     In  regard  to  the  rise 


HISTORICAL  GEOLOGY  113 

of  evolution  in  America,  more  can  be  had  from  Dana's 
paper  on  Asa  Gray  (35,  181,  1888).  Here  we  read,  as  a 
sequel  to  his  Thoughts  on  Species,  that  the  **  paper  may 
be  taken,  perhaps,  as  a  culmination  of  the  past,  just  as 
the  new  future  was  to  make  its  appearance.''  Finally, 
in  this  connection  there  should  be  mentioned  0.  0. 
Marsh's  paper  on  Thomas  Henry  Huxley  (50,  177, 1895), 
wherein  is  recorded  the  latter 's  share  in  the  upbuilding 
of  the  evolutionary  theory. 

We  have  seen  that  originally  Dana  was  a  creationist, 
but  in  the  course  of  his  long  and  fruitful  life  he  gradually 
became  an  evolutionist,  and  rather  a  Neo-Lamarckian 
than  a  Darwinian.  This  change  may  be  traced  in  the 
various  editions  of  his  Manual  of  Geology,  and  in  the  last 
edition  of  1895  he  says  his  ** speculative  conclusions"  of 
1852  in  regard  to  the  origin  of  species  are  not  *  *  in  accord 
with  the  author 's  present  judgment. "  *  ^  The  evidence  in 
favor  of  evolution  by  variation  is  now  regarded  as  essen- 
tially complete."  On  the  other  hand,  while  man  is 
^'unquestionably"  closely  related  in  structure  to  the 
man-apes,  yet  he  is  not  linked  to  them  but  stands  apart, 
through  *Hhe  intervention  of  a  Power  above  Nature. 
.  .  .  Believing  that  Nature  exists  through  the  will  and 
ever-acting  power  of  the  Divine  Being,  and  .  .  .  that  the 
whole  Universe  is  not  merely  dependent  on,  but  actually 
is,  the  Will  of  one  Supreme  Intelligence,  Nature,  with 
Man  as  its  culminant  species,  is  no  longer  a  mystery." 

In  America  most  of  the  paleontologists  are  Neo- 
Lamarckian,  a  school  that  was  developed  independently 
by  E.  D.  Cope  (1840-1897)  through  the  vertebrate  evi- 
dence, and  by  Alpheus  Hyatt  (1838-1902)  mainly  on  the 
evidence  of  the  ammonites.  They  hold  that  variations 
and  acquired  characters  arise  through  the  effects  of  the 
environment,  the  mechanics  of  the  organism  resulting 
from  the  use  and  disuse  of  organs,  etc.  One  of  the  lead- 
ing exponents  of  this  school  is  A.  S.  Packard,  whose  book 
on  Lamarck,  His  Life  and  Work,  1901,  fully  explains  the 
doctrines  of  the  Neo-Lamarckians. 

The  Growth  of  Invertebrate  JPaleontology, 

How  and  by  whom  paleontology  has  been  developed 
has  been  fully  stated  in  the  Journal  in  a  very  clear  man- 


114  A  CENTURY  OF  SCIENCE 

ner  by  Professor  Marsh  in  his  memorable  presidential 
address  of  1879,  History  and  Methods  of  Palasontological 
Discovery  (18,  323,  1879),  and  by  Karl  von  Zittel  in  his 
most  interesting  book,  History  of  Geology  and  Palaeon- 
tology, 1901.  In  this  discussion  we  shall  largely  follow 
Marsh. 

The  science  of  paleontology  has  passed  through  four 
periods,  the  first  of  them  the  long  Mystic  period  extend- 
ing up  to  the  beginning  of  the  seventeenth  century,  when 
the  idea  that  fossils  were  once  living  things  was  only 
rarely  perceived.  The  second  period  was  the  Diluvial 
period  of  the  eighteenth  century,  when  nearly  everyone 
regarded  the  fossils  as  remains  of  the  Noachian  deluge. 
With  the  beginnings  of  the  nineteenth  century  there 
arose  in  western  Europe  the  knowledge  that  fossils  are 
the  *^  medals  of  creation '^  and  that  they  have  a  chrono- 
genetic  significance ;  also  that  life  had  been  periodically 
destroyed  through  world-wide  convulsions  in  nature. 
From  about  1800  to  1860  was  the  time  of  the  creationists 
and  catastrophists,  which  may  be  known  as  the  Catas- 
trophic period.  The  fourth  period  began  in  1860  with 
Darwin's  Origin  of  Species.  Since  that  time  the  theory 
of  evolution  has  pervaded  all  work  in  paleontology,  and 
accordingly  this  time  may  be  known  as  the  Evolutionary 
period. 

Mystic  Period. — The  Mystic  period  in  paleontology 
begins  with  the  Greeks,  five  centuries  before  the  present 
era,  and  continues  down  to  the  beginning  of  the  seven- 
teenth century  of  our  time.  Some  correctly  saw  that  the 
fossils  were  once  living  marine  animals,  and  that  the  sea 
had  been  where  they  now  occur.  Others  interpreted  fos- 
sil mammal  bones  as  those  of  human  giants,  the  Titans, 
but  the  Aristotelian  view  that  they  were  of  spontaneous 
generation  through  the  hidden  forces  of  the  earth  domi- 
nated all  thought  for  about  twenty  centuries. 

In  the  sixteenth  century  canals  were  being  dug  in 
Northern  Italy,  and  the  many  fossils  so  revealed  led  to  a 
fierce  discussion  as  to  their  actual  nature.  Leonardo  da 
Vinci  (1452-1519)  opposed  the  commonly  accepted  view 
of  their  spontaneous  generation  and  said  that  they  were 
the  remains  of  once  living  animals  and  that  the  sea  had 
been  where  they  occur.     *'You  tell  me,*'  he  said,  **that 


HISTORICAL  GEOLOGY  115 

Nature  and  the  influence  of  the  stars  have  formed  these 
shells  in  the  mountains;  then  show  me  a  place  in  the 
mountains  where  the  stars  at  the  present  day  make  shelly 
forms  of  different  ages,  and  of  different  species  in  the 
same  place.''  However,  nothing  came  of  his  teachings 
and  those  of  his  countryman  Fracastorio  (1483-1553), 
who  further  ridiculed  the  idea  that  they  were  the 
remains  of  the  deluge.  The  first  mineralogist,  Agricola, 
described  them  as  minerals — fossilia — and  said  that  they 
arose  in  the  ground  from  fatty  matter  set  in  fermenta- 
tion by  heat.  Others  said  that  they  were  freaks  of 
nature.  Martin  Lister  (1638-1711)  figured  fossils  side 
by  side  with  living  shells  to  show  that  they  were  extinct 
forms  of  life.  In  the  seventeenth  century,  and  especially 
in  Italy  and  Germany,  many  books  were  published  on 
fossils,  some  with  illustrations  so  accurate  that  the 
species  can  be  recognized  to-day.  Finally,  toward 
the  close  of  this  century  the  influence  of  Aristotle  and  the 
scholastic  tendency  to  disputation  came  more  or  less  to 
an  end.  Fossils  were  already  to  many  naturalists  once 
living  plants  and  animals.  Marsh  states:  *^The  many 
collections  of  fossils  that  had  been  brought  together,  and 
the  illustrated  works  that  had  been  published  about  them, 
were  a  foundation  for  greater  progress,  and,  with  the 
eighteenth  century,  the  second  period  in  the  history  of 
paleontology  began.'' 

Diluvial  Period. — During  the  eighteenth  century  many 
more  books  on  fossils  were  published  in  western  Europe, 
and  now  the  prevalent  explanation  was  that  they  were 
the  remains  of  the  Noachian  deluge.  For  nearly  a  cen- 
tury theologians  and  laymen  alike  took  this  view,  and 
some  of  the  books  have  become  famous  on  this  account, 
but  the  diluvial  views  sensibly  declined  with  the  close 
of  the  eighteenth  century. 

The  true  nature  of  fossils  had  now  been  clearly  deter- 
mined. They  were  the  remains  of  plants  and  animals, 
deposited  long  before  the  deluge,  part  in  fresh  water  and 
part  in  the  sea.  *  *  Some  indicated  a  mild  climate,  and  some 
the  tropics.  That  any  of  these  were  extinct  species,  was 
as  yet  only  suspected. ' '  Yet  before  the  close  of  the  cen- 
tury there  were  men  in  England  and  France  who  pointed 
out  that  different  formations  had  different  fossils  and 


116  A  CENTURY  OF  SCIENCE 

that  some  of  them  were  extinct.  These  views  then  led  to 
many  fantastic  theories  as  to  how  the  earth  was  formed — 
dreams,  most  of  them  have  been  called.     Marsh  says : 

*'The  dominant  idea  of  the  first  sixteen  centuries  of  the 
present  era  was,  that  the  universe  was  made  for  Man.  This  was 
the  great  obstacle  to  the  correct  determination  of  the  position 
of  the  earth  in  the  universe,  and,  later,  of  the  age  of  the  earth. 
.  In  a  superstitious  age,  when  every  natural  event  is 
referred  to  a  supernatural  cause,  science  cannot  live  .  .  . 
Scarcely  less  fatal  to  the  growth  of  science  is  the  age  of  Author- 
ity, as  the  past  proves  too  well.  With  freedom  of  thought,  came 
definite  knowledge,  and  certain  progress; — ^but  two  thousand 
years  was  long  to  wait.*' 

One  of  the  most  significant  publications  of  this  period 
was  Linnaeus 's  Systema  Naturae,  which  appeared  in  1735. 
In  this  work  was  introduced  binomial  nomenclature,  or 
the  system  of  giving  each  plant  and  animal  species  a 
generic  and  specific  name,  as  Felis  leo  for  the  lion.  The 
system  was,  however,  not  established  until  the  tenth 
edition  of  the  work  in  1758,  which  became  the  starting 
point  of  zoological  nomenclature.  Since  then  there  has 
been  added  another  canon,  the  law  of  priority,  which 
holds  that  the  first  name  applied  to  a  given  form  shall 
stand  against  all  later  names  given  to  the  same  organism. 

Catastrophic  Period. — With  the  beginning  of  the  nine- 
teenth century  there  started  a  new  era  in  paleontology, 
and  this  was  the  time  when  the  foundations  of  the  science 
were  laid.  The  period  continued  for  six  decades,  or  until 
the  time  of  the  Origin  of  Species.  Marsh  saj^s  that  now 
**  method  replaced  disorder,  and  systematic  study  super- 
seded casual  observation."  Fossils  were  accurately 
determined,  comparisons  were  made  with  living  forms, 
and  the  species  named  according  to  the  binomial  system. 
However,  every  species,  recent  and  extinct,  was  regarded 
as  a  separate  creation,  and  because  of  the  usually  sharp 
separation  of  the  superposed  fossil  faunas  and  floras, 
these  were  held  to  have  been  destroyed  through  a  series 
of  periodic  catastrophes  of  which  the  Noachian  deluge 
was  the  last. 

Lamarck  between  1802  and  1806  described  the  Tertiary 
shells  of  the  Paris  basin.     Comparing  them  with  the  liv- 


HISTOEICAL  GEOLOGY  117 

ing  forms,  he  saw  that  most  of  the  fossils  were  of  extinct 
species,  and  in  this  way  he  came  to  be  the  founder  of 
modern  invertebrate  paleontology.  He  also  maintained 
after  1801  that  life  has  been  continuous  since  its  origin 
and  that  nature  has  been  uniform  in  the  course  of  its 
development.     Marsh  adds : 

**His  researches  on  the  invertebrate  fossils  of  the  Paris  Basin, 
although  less  striking,  were  not  less  important  than  those  of 
Cuvier  on  the  vertebrates ;  while  the  conclusions  he  derived  from 
them  form  the  basis  of  modern  biology. '^ 

' '  Lamarck  was  the  prophetic  genius,  half  a  century  in  advance 
of  his  time." 

Cuvier  established  comparative  anatomy  and  verte- 
brate paleontology,  and  was  one  of  the  first  to  point  out 
that  fossil  animals  are  nearly  all  extinct  forms.  He 
came  to  the  latter  conclusion  in  1796  through  a  study  of 
fossil  elephants  found  in  Europe.  **  Cuvier  enriched 
the  animal  kingdom  by  the  introduction  of  fossil  forms 
among  the  living,  bringing  all  together  into  one  compre- 
hensive system."  This  opened  to  him  entirely  new 
views  respecting  the  theory  of  the  earth,  and  he  devoted 
more  than  twenty-five  years  to  developing  the  theories 
of  special  creation  and  catastrophism,  described  in  his 
Discourse  on  the  Revolutions  of  the  Surface  of  the  Globe. 
**With  all  his  knowledge  of  the  earth,  he  could  not  free 
himself  from  tradition,  and  believed  in  the  universality 
and  power  of  the  Mosaic  deluge.  Again,  he  refused  to 
admit  the  evidence  brought  forward  by  his  distinguished 
colleagues  against  the  permanence  of  species,  and  used 
all  his  great  influence  to  crush  out  the  doctrine  of  evolu- 
tion, then  first  proposed''  (Marsh). 

In  England  it  was  William  Smith  (1769-1839)  who 
independently  discovered  the  chronogenetic  significance 
of  fossils,  and  in  their  stratigraphic  superposition  indi- 
cated the  way  for  the  study  of  historical  geology.  He 
first  published  on  this  matter  in  1799,  but  his  completed 
statements  came  in  works  entitled  *  *  Strata  identified  by 
Organized  Fossils,''  1816-1820,  and  * ' Stratigraphical 
System  of  Organized  Fossils,"  1817. 

Invertebrate  paleontology  in  America  during  the 
Catastrophic  period  had  its  beginning  in  Lesueur,  who 


118  A  CENTURY  OF  SCIENCE 

in  1818  described  the  Ordovician  gastropod  Maclurites 
magna.  All  of  the  paleontologists  of  this  time  were  sat- 
isfied to  describe  species  and  genera  and  to  ascertain  in  a 
broad  way  the  stratigraphic  significance  of  the  fossil 
faunas  and  floras.  James  Hall  in  1854  (17,  312)  knew  of 
1588  species,  described  and  undescribed,  in  the  New  York 
system,  while  in  England  Morris  listed  in  that  year  8300 
Paleozoic  forms.  In  1856  Dana  recites  the  known  fossil 
species  as  follows  (22,  333) :  The  whole  number  of 
known  American  species  of  animals  of  the  Permian  to 
Recent  is  about  2000 ;  while  in  Britain  and  Europe,  there 
were  over  20,000  species.  In  the  Permian  we  have  none, 
while  Europe  has  over  200  species.  In  the  Triassic  we 
have  none,  Europe  1000  species;  Jurassic  60,  Europe 
over  4000;  Cretaceous  350  to  400,  Europe  about  6000; 
Tertiary  hardly  1500,  Europe  about  8000.  Since  that 
time  nearly  all  of  the  larger  American  Paleozoic  faunas 
have  been  developed,  but  there  are  thousands  of  species 
yet  to  be  described.  Who  the  more  prominent  American 
paleontologists  of  this  period  were  has  been  told  in  the 
section  on  the  development  of  the  geological  column. 

The  grander  paleontologic  results  of  the  Catastrophic 
period  have  been  so  well  stated  by  Marsh  that  it  is  worth 
our  while  to  repeat  them  here : 

**It  had  now  been  proved  beyond  question  that  portions  at 
least  of  the  earth's  surface  had  been  covered  many  times  by  the 
sea,  with  alternations  of  fresh  water  and  of  land ;  that  the  strata 
thus  deposited  were  formed  in  succession,  the  lowest  of  the  series 
being  the  oldest;  that  a  distinct  succession  of  animals  and 
plants  had  inhabited  the  earth  during  the  different  geological 
periods;  and  that  the  order  of  succession  found  in  one  part  of 
the  earth  was  essentially  the  same  in  all.  More  than  30,000  new 
species  of  extinct  animals  and  plants  had  now  been  described. 
It  had  been  found,  too,  that  from  the  oldest  formations  to  the 
most  recent,  there  had  been  an  advance  in  the  grade  of  life,  both 
animal  and  vegetable,  the  oldest  forms  being  among  the  simplest, 
and  the  higher  forms  successively  making  their  appearance. 

It  had  now  become  clearly  evident,  moreover,  that  the  fossils 
from  the  older  formations  were  all  extinct  species,  and  that  only 
in  the  most  recent  deposits  were  there  remains  of  forms  still 
living  .  .  .  Another  important  conclusion  reached,  mainly 
through  the  labors  of  Lyell,  was,  that  the  earth  had  not  been 
subjected  in  the  past  to  sudden  and  violent  revolutions ;  but  the 


HISTORICAL  GEOLOGY  119 

great  changes  wrought  had  been  gradual,  differing  in  no  essen- 
tial respect  from  those  still  in  progress.  Strangely  enough,  the 
corollary  to  this  proposition,  that  life,  too,  had  been  continuous 
on  the  earth,  formed  at  that  date  no  part  of  the  common  stock 
of  knowledge.  In  the  physical  world,  the  great  law  of  *  cor- 
relation of  forces'  had  been  announced,  and  widely  accepted; 
but  in  the  organic  world,  the  dogma  of  the  miraculous  creation 
of  each  separate  species  still  held  sway." 

Evolutionary  Period. — This  period  begins  with  1860 
and  the  publication  of  Darwin's  Origin  of  Species  (late 
in  1859).  It  is  the  period  of  modern  paleontology,  and  is 
dominated  by  the  belief  that  universal  laws  pervade  not 
only  inorganic  matter,  but  all  life  as  well.  Louis  Agas- 
siz  had  been  in  America  fourteen  years  when  Darwin's 
book  appeared,  and  his  wonderful  influence  in  bringing 
the  zoology  of  our  country  to  a  high  stand  and  the 
further  influence  he  exerted  through  his  students  was 
bound  to  react  beneficially  on  invertebrate  paleontology. 
Shortly  after  the  beginning  of  this  period,  or  in  1867, 
Alpheus  Hyatt,  one  of  Agassiz  's  students,  began  to  apply 
the  study  of  embryology  to  fossil  cephalopods,  showing 
clearly  that  these  shells  retain  a  great  deal  of  their 
growth  stages  or  ontogeny.  This  method  of  study  was 
then  followed  by  R.  T.  Jackson,  C.  E.  Beecher,  and  J. 
P.  Smith,  and  has  been  productive  of  natural  classifica- 
tions of  the  Cephalopoda,  Brachiopoda,  Trilobita,  and 
Echinoidea. 

The  dominant  invertebrate  paleontologist  of  this 
period  was  of  course  James  Hall,  who  described  about 
5000  species  of  American  Paleozoic  fossils.  He  also 
built  up  the  New  York  State  Museum,  while  around  his 
private  collections  of  fossils  have  been  developed  the 
American  Museum  of  Natural  History  in  New  York  City 
and  the  Walker  Museum  at  the  University  of  Chicago. 
In  his  most  important  laboratory  of  paleontology  at 
Albany,  there  have  been  trained  either  wholly  or  in 
part  the  following  paleontologists:  F.  B.  Meek,  C.  A. 
White,  R.  P.  Whitfield,  C.  D.  Walcott,  C.  E.  Beecher, 
John  M.  Clarke,  and  Charles  Schuchert. 

In  Canada,  through  the  work  of  the  Geological  Survey 
of  the  Dominion,  came  the  paleontoloerists  Elkanah 
Billings  and,  later  on,  J.  F.  Whiteaves.     The  ^'father  of 


120  A  CENTURY  OF  SCIENCE 

Canadian  paleontology,''  Sir  "William  Dawson,  who 
developed  independently,  was  active  in  all  branches  of 
the  science  and  did  much  to  unravel  the  geology  of 
eastern  Canada.  No  organism  has  been  more  discussed 
and  more  often  rejected  and  accepted  as  a  fossil  than  his 
**dawn  animal  of  Canada,"  Eozoon  canadense,  first 
described  in  1865.  His  son,  George  M.  Dawson,  was  one 
of  the  directors  of  the  Geological  Survey  of  Canada. 
Finally  the  extensive  paleontology  of  the  Cambrian  of 
Canada  was  worked  out  by  another  self-made  paleontolo- 
gist, G.  F.  Matthew. 

Paleobotany. — American  paleobotany  was  developed 
during  this,  the  fourth  period,  through  the  state  and 
national  surveys,  first  in  Leo  Lesquereux,  a  Swiss  stu- 
dent induced  by  Agassiz  to  come  to  America,  and  in  J.  S. 
Newberry.  The  second  generation  of  paleobotanists  is 
represented  by  Lester  F.  Ward  and  W.  N.  Fontaine, 
and  the  third  generation,  the  present  workers,  includes 
F.  H.  Knowlton,  David  White,  Arthur  Hollick,  and  E.  W. 
Berry.  A  new  line  of  paleobotanical  work,  the  histology 
of  woody  but  pseudomorphous  remains,  has  been  devel- 
oped by  G.  R.  Wieland. 

The  grander  results  of  the  study  of  paleontology  dur- 
ing the  evolutionary  period  may  be  summed  up  with  the 
conclusions  of  Marsh : 

''One  of  the  main  characteristics  of  this  epoch  is  the  belief 
that  all  life,  living  and  extinct,  has  been  evolved  from  simple 
forms.  Another  prominent  feature  is  the  accepted  fact  of  the 
great  antiquity  of  the  human  race.  These  are  quite  sufficient 
to  distinguish  this  period  sharply  from  those  that  preceded  it. 

Charles  Darwin's  work  at  once  aroused  attention,  and  brought 
about  in  scientific  thought  a  revolution  which  ''has  influenced 
paleontology  as  extensively  as  any  other  department  of  science 
.  .  .  In  the  [previous  period]  species  were  represented  inde- 
pendently by  parallel  lines;  in  the  present  period,  they  are 
indicated  by  dependent,  branching  lines.  The  former  was  the 
analytic,  the  latter  is  the  synthetic  period." 

Synthetic  Period. — Wliat  is  to  be  the  next  trend  in 
paleontology?  Clearly  it  is  to  be  the  Synthetic  period, 
one  that  Marsh  in  1879  indicated  in  these  words:  "But 
if  we  are  permitted  to  continue  in  imagination  the  rap- 
idly converging  lines  of  research  pursued  to-day,  they 


HISTORICAL  GEOLOGY  121 

seem  to  meet  at  the  point  where  organic  and  inorganic 
nature  become  one.  That  this  point  will  yet  be  reached, 
I  cannot  doubt. ' ' 

This  Synthetic  period,  foreshadowed  also  in  Herbert 
Spencer's  Synthetic  Philosophy,  has  not  yet  arrived,  but 
before  long  another  great  leader  will  appear.  We  have 
the  prophecy  of  his  coming  in  such  books  as  The  Fitness 
of  the  Environment,  by  Lawrence  J.  Henderson,  1913; 
The  Origin  and  Nature  of  Life,  by  Benjamin  Moore, 
1913;  The  Organism  as  a  Whole,  by  Jacques  Loeb,  1916; 
and  The  Origin  and  Evolution  of  Life,  by  Henry  F. 
Osborn,  1917. 

In  all  nature,  inorganic  and  organic,  there  is  continuity 
and  consistency,  beauty  and  design.  We  are  beginning 
to  see  that  there  are  eternal  laws,  ever  interacting  and 
resulting  in  progressive  and  regressive  evolutions.  The 
realization  of  these  scientific  revelations  kindles  in  us  a 
desire  for  more  knowledge,  and  the  grandest  revelations 
are  yet  before  us  in  the  synthesis  of  the  sciences. 

Notes, 

^  For  more  detail  in  regard  to  these  tillites  and  the  older  ones  see  Climates 
of  Geologic  Time,  by  Charles  Schuchert,  being  Chapter  XXI  in  Hunting- 
ton's  Climatic  Factor  as  Illustrated  in  Arid  America,  Publication  No. 
192  of  the  Carnegie  Institution  of  Washington,  1914,  Also  Arthur  P. 
Coleman's  presidential  address  before  the  Geological  Society  of  America 
in  1915,  Dry  Land  in  Geology,  published  in  the  Society's  Bulletin,  27, 
175,  1916. 


Ill 

A  CENTURY  OF  GEOLOGY STEPS  OF  PROG- 
RESS IN  THE  INTERPRETATION  OF 
LAND  FORMS 

By  HERBERT  E.  GREGORY 

THE  essence  of  physiography  is  the  belief  that  land 
forms  represent  merely  a  stage  in  the  orderly  devel- 
opment of  the  earth's  surface  features;  that  the 
various  dynamic  agents  perform  their  characteristic  work 
throughout  all  geologic  time.  The  formulation  of  prin- 
ciple and  processes  of  earth  sculpture  was,  therefore, 
impossible  on  the  hypothesis  of  a  ready-made  earth 
whose  features  were  substantially  unchangeable,  except 
when  modified  by  catastrophic  processes.  In  1821,  J.  W. 
Wilson  wrote  in  the  Journal:  **Is  it  not  the  best  theory 
of  the  earth,  that  the  Creator,  in  the  beginning,  at  least 
at  the  general  deluge,  formed  it  with  all  its  present  grand 
characteristic  features?"^  If  so,  a  search  for  causes  is 
futile,  and  the  study  of  the  work  performed  by  streams 
and  glaciers  and  wind  is  unprofitable.  The  belief  in  the 
Deluge  as  the  one  great  geological  event  in  the  history  of 
the  earth  has  brought  it  about  that  the  speculations  of 
Aristotle,  Herodotus,  Strabo,  and  Ovid,  and  the  illus- 
trious Arab,  Avicenna  (980-1037),  unchecked  by  appeal 
to  facts  but  also  unopposed  by  priesthood  or  popular 
prejudice,  are  nearer  to  the  truth  than  the  intolerant  con- 
troversial writings  of  the  intellectual  leaders  whose 
touchstone  was  orthodoxy.  A  few  thinkers  of  the  six- 
teenth century  revolted  against  the  interminable  repeti- 
tion of  error,  and  Peter  Severinus  (1571)  advised  his 
students :  *  ^  Burn  up  your  books  .  .  .  buy  yourselves 
stout  shoes,  get  away  to  the  mountains,  search  the  valleys, 
the  deserts,  the  shores  of  the  seas.  ...  In  this  way  and  no 


INTERPRETATION  OF  LAND  FORMS       123 

other  will  you  arrive  at  a  knowledge  of  things.''  But 
the  thorough-going  ''diluvialisf'  who  believed  that  a 
million  species  of  animals  could  occupy  a  450-foot 
Ark,  but  not  that  pebbles  weathered  from  rock  or  that 
rivers  erode,  had  no  use  for  his  powers  of  observation. 

Sporadic  germs  of  a  science  of  land  forms  scattered 
through  the  literature  of  the  seventeenth  and  eighteenth 
centuries  found  an  unfavorable  environment  and  pro- 
duced inconspicuous  growths.  Even  their  sponsors  did 
little  to  cultivate  them.  Steno  (1631-1687)  mildly  sug- 
gested that  surface  sculpturing,  particularly  on  a  small 
scale,  is  largely  the  work  of  running  water,  and  Guettard 
(1715-1786),  a  truly  great  mind,  grasped  the  fundamental 
principles  of  denudation  and  successfully  entombed  his 
views  as  well  as  his  reputation  in  scores  of  books  and  vol- 
umes of  cumbrous  diffuse  writing. 

At  the  beginning  of  the  nineteenth  century  a  sufficient 
body  of  principles  had  been  established  to  justify  the 
recognition  of  an  earth  science,  geology,  and  the  195  vol- 
umes of  the  Journal  thus  far  published  carry  a  large  part 
of  the  material  which  has  won  approval  for  the  new 
science  and  given  prominence  to  American  thought. 
From  the  pages  in  the  Journal,  the  progress  of  geology 
may  be  illustrated  by  tracing  the  fluctuation  in  the  devel- 
opment of  fact  and  theory  as  relates  to  valleys  and  gla- 
cial features,  the  subjects  to  which  this  chapter  is  devoted. 

The  Interpretation  of  Valleys, 
The  Pioneers. 

Desmarest  (1725-1815)  might  be  styled  the  father  of 
physiography.  By  concrete  examples  and  sound  induc- 
tion he  established  (1774)  the  doctrine  that  the  valleys  of 
central  France  are  formed  by  the  streams  which  occupy 
them.  He  also  made  the  first  attempt  to  trace  the  his- 
tory of  a  landscape  through  its  successive  stages  on  the 
basis  of  known  causes.  His  methods  and  reasoning  are 
practically  identical  with  those  of  Button  working  in  the 
ancient  lavas  of  New  Mexico ;  and  Whitney'^  description 
of  the  Table  Mountains  of  California  might  well  have 
appeared  in  Desmarest 's  memoirs.^  The  teachings  of 
Desmarest  were  strengthened  and  expanded  by  DeSaus- 


124  A  CENTURY  OF  SCIENCE 

sure  (1740-1799),  the  sponsor  for  the  term,  '^ Geology,'' 
(1779)  who  saw  in  the  intimate  relation  of  Alpine 
streams  and  valleys  the  evidence  of  erosion  by  running 
water  (1786). 

The  work  of  these  acknowledged  leaders  of  geological 
thought  attracted  singularly  little  attention  on  the  Con- 
tinent, and  Lamarck  ^s  volume  on  denudation  (Hydro- 
geologie),  which  appeared  in  1802,  although  an  important 
contribution,  sank  out  of  sight.  But  the  seed  of  the  French 
school  found  fertile  ground  in  Edinburgh,  the  center  of 
the  geological  world  during  the  first  quarter  of  the  nine- 
teenth century.  Button's  ** Theory  of  the  Earth,  with 
Proofs  and  Illustrations,'^  in  which  the  guidance  of 
DeSaussure  and  Desmarest  is  gratefully  acknowledged, 
appeared  in  1795.  The  original  publication  aroused  only 
local  interest,  but  when  placed  in  attractive  form  by  Play- 
fair's  *' Illustrations  of  the  Huttonian  Theory"  (1802), 
the  problem  of  the  origin  and  development  of  land  forms 
assumed  a  commanding  position  in  geological  thought. 
Hutton  was  peculiarly  fortunate  in  his  environment.  He 
had  the  support  and  assistance  of  a  group  of  able  scien- 
tific colleagues  as  well  as  the  bitter  opposition  of  Jameson 
and  of  the  defenders  of  orthodoxy.  His  views  were 
discussed  in  scientific  publications  and  found  their  way  to 
literary  and  theological  journals.  Hutton 's  conception 
of  the  processes  of  land  sculpture — slow  upheaving  and 
slow  degradation  of  mountains,  differential  weathering, 
and  the  carving  of  valleys  by  streams — has  a  very 
modern  aspect.  Playf air's  book  would  scarcely  be  out  of 
place  in  a  twentieth  century  class  room.  The  following 
paragraphs  are  quoted  from  it:^ 

**  ...  A  river,  of  which  the  course  is  both  serpentine  and 
deeply  excavated  in  the  rock,  is  among  the  phenomena,  by 
which  the  slow  waste  of  the  land,  and  also  the  cause  of  that 
waste,  are  most  directly  pointed  out. 

The  structure  of  the  vallies  among  mountains,  shews  clearly  to 
what  cause  their  existence  is  to  be  ascribed.  Here  we  have  first 
a  large  valley,  communicating  directly  with  the  plain,  and  wind- 
ing between  high  ridges  of  mountains,  while  the  river  in  the 
bottom  of  it  descends  over  a  surface,  remarkable,  in  such  a 
scene,  for  its  uniform  declivity.  Into  this,  open  a  multitude  of 
transverse  or  secondary  vallies,  intersecting  the  ridges  on  either 


INTERPRETATION  OF  LAND  FORMS       125 

side  of  the  former,  each  bringing  a  contribution  to  the  main 
stream,  proportioned  to  its  magnitude;  and,  except  where  a 
cataract  now  and  then  intervenes,  all  having  that  nice  adjust- 
ment in  their  levels,  which  is  the  more  wonderful,  the  greater 
the  irregularity  of  the  surface.  These  secondary  vallies  have 
others  of  a  smaller  size  opening  into  them;  and,  among  moun- 
tains of  the  first  order,  where  all  is  laid  out  on  the  greatest  scale, 
these  ramifications  are  continued  to  a  fourth,  and  even  a  fifth, 
each  diminishing  in  size  as  it  increases  in  elevation,  and  as  its 
supply  of  water  is  less.  Through  them  all,  this  law  is  in  gen- 
eral observed,  that  where  a  higher  valley  joins  a  lower  one,  of 
the  two  angles  which  it  makes  with  the  latter,  that  which  is 
obtuse  is  always  on  the  descending  side;  .  .  .  what  else  but  the 
water  itself,  working  its  way  through  obstacles  of  unequal 
resistance,  could  have  opened  or  kept  up  a  communication 
between  the  inequalities  of  an  irregular  and  alpine  surface  .  .  . 

.  .  .  The  probability  of  such  a  constitution  [arrangement  of 
valleys]  having  arisen  from  another  cause,  is,  to  the  probability 
of  its  having  arisen  from  the  running  of  water,  in  such  a  pro- 
portion as  unity  bears  to  a  number  infinitely  great. 

.  .  .  With  Dr.  Hutton,  we  shall  be  disposed  to  consider  those 
great  chains  of  mountains,  which  traverse  the  surface  of  the 
globe,  as  cut  out  of  masses  vastly  greater,  and  more  lofty  than 
any  thing  that  now  remains. 

From  this  gradual  change  of  lakes  into  rivers,  it  follows,  that 
a  lake  is  but  a  temporary  and  accidental  condition  of  a  river, 
which  is  every  day  approaching  to  its  termination;  and  the 
truth  of  this  is  attested,  not  only  by  the  lakes  that  have  existed, 
but  also  by  those  that  continue  to  exist.'' 

Steps  Backward, 

Even  Hutton 's  clear  reasoning,  firmly  buttressed  by 
concrete  examples,  was  insufficient  to  overcome  the  belief 
in  ready-made  or  violently  formed  valleys  and  original 
corrugations  and  irregularities  of  mountain  surface. 
The  pages  of  the  Journal  show  that  the  principles  laid 
down  by  Playfair  were  too  far  in  advance  of  the  times  to 
secure  general  acceptance.  In  the  first  volume  of  the 
Journal,  the  gorge  of  the  French  Broad  River  is  assigned 
by  Kain  to  ^^some  dreadful  commotion  in  nature  which 
probably  shook  these  mountains  to  their  bases,  "^  and 
the  gorge  of  the  lower  Connecticut  is  considered  by 
Hitchcock  (1824)^  as  a  breach  which  drained  a  series  of 
lakes  **not  many  centuries  before  the  settlement  of  this 


126  A  CENTURY  OF  SCIENCE 

country. ' '  The  prevailing  American  and  English  view  for 
the  first  quarter  of  the  nineteenth  century  is  expressed 
in  the  reviews  in  this  Journal,  where  the  well-known 
conclusions  of  Conybeare  and  Phillips  that  streams  are 
incompetent  to  excavate  valleys  are  quoted  with  approval 
and  admiration  is  expressed  for  Buckland's  famous 
**  Reliquiae  Diluvianse, "  a  300-page  quarto  volume  devoted 
to  proof  of  a  deluge.  The  professor  at  Yale,  Silliman, 
and  the  professor  at  Oxford,  Buckland,  saw  that  an 
acceptance  of  Hutton's  views  involved  a  repudiation  of 
the  Biblical  flood,  and  much  space  is  devoted  to  combating 
these  *  *  erroneous ' '  and  *  ^  unscientific ' '  views.  For  exam- 
ple, Buckland  says:^ 

*'.  .  .  The  general  belief  is,  that  existing  streams,  avalanches 
and  lakes,  bursting  their  barriers,  are  sufficient  to  account  for 
all  their  phenomena,  and  not  a  few  geologists,  especially  those 
of  the  Huttonian  school,  at  whose  head  is  Professor  Playfair, 
have  till  recently  been  of  this  opinion.  .  .  .  But  it  is  now  very 
clear  to  almost  every  man,  who  impartially  examines  the  facts 
in  regard  to  existing  vallies,  that  the  causes  now  in  action,  men- 
tioned above,  are  altogether  inadequate  to  their  production; 
nay,  that  such  a  supposition  would  involve  a  physical  impossi- 
bility. We  do  not  believe  that  one-thousandth  part  of  our 
present  vallies  were  excavated  by  the  power  of  existing  streams. 
...  In  very  many  cases  of  large  rivers,  it  is  found,  that  so  far 
from  having  formed  their  own  beds,  they  are  actually  in  a  grad- 
ual manner  filling  them  up. 

Again ;  how  happens  it  that  the  source  of  a  river  is  frequently 
below  the  head  of  a  valley,  if  the  river  excavated  that  valley  ? 

The  most  powerful  argument,  however,  in  our  opinion, 
against  the  supposition  we  are  combating,  is  the  phenomena  of 
transverse  and  longitudinal  valleys;  both  of  which  could  not 
possibly  have  been  formed  by  existing  streams." 

Phillips  writes  in  1829:"^  '*The  excavation  of  valleys 
can  be  ascribed  to  no  other  cause  than  a  great  flood  of 
water  which  overtopped  the  hills,  whose  summits  those 
vallies  descend. '^ 

Faith  in  Noah's  flood  as  the  dominant  agent  of  erosion 
rapidly  lost  ground  through  the  teaching  of  Lyell  after 
1830,  but  the  theory  of  systematic  development  of  land- 
scapes by  rivers  gained  little.  In  fact,  Scrope  in  1830,^ 
in  showing  that  the  entrenched  meanders  of  the  Moselle 


INTERPRETATION  OF  LAND  FORMS       127 

prove  gradual  progressive  stream  work,  was  in  advance 
of  his  Englisli  contemporary.  Judged  by  contributions 
to  the  Journal,  Ly ell's  teaching  served  to  standardize 
American  opinion  of  earth  sculpture  somewhat  as  fol- 
lows: The  ocean  is  the  great  valley  maker,  but  rivers 
also  make  them ;  the  position  of  valleys  is  determined  by 
original  or  renewed  surface  inequalities  or  by  faulting; 
exceptional  occurrences — earthquakes,  bursting  of  lakes, 
upheavals  and  depressions — have  played  an  important 
part.  Hayes  (1839)^  thought  that  the  surface  of  New 
York  was  essentially  an  upraised  sea-bottom  modified  by 
erosion  of  waves  and  ocean  currents.  Sedgwick  (1838)^^ 
considered  high-lying  lake  basins  proof  of  valleys  which 
were  shaped  under  the  sea.  Many  of  the  valleys  in  the 
Chilian  Cordillera  were  thought  by  Darwin  (1844)  to 
have  been  the  work  of  waves  and  tides,  and  water  gaps 
are  ascribed  to  currents  ^*  bursting  through  the  range  at 
those  points  where  the  strata  have  been  least  inclined 
and  the  height  consequently  is  less.''  Speaking  of  the 
magnificent  stream-cut  canyons  of  the  Blue  Mountains 
of  New  South  Wales,  gorges  which  lead  to  narrow  exits 
through  monoclines,  Darwin  says:  ^^To  attribute  these 
hollows  to  alluvial  action  would  be  preposterous.''^^ 

The  influence  of  structure  in  the  formation  of  valleys 
is  emphasized  by  many  contributors  to  the  Journal. 
Hildreth  in  1836,  in  a  valuable  paper,^^  which  is  perhaps 
the  first  detailed  topographic  description  of  drainage  in 
folded  strata,  expresses  the  opinion  that  the  West  Vir- 
ginia ridges  and  valleys  antedated  the  streams  and  that 
water  gaps  though  cut  by  rivers  involve  pre-existing 
lakes.  Geddes  (1826)^^  denied  that  Niagara  River  cut  its 
channel  and  speaks  of  valleys  which  ^^were  valleys  e'er 
moving  spirit  bade  the  waters  flow."  Conrad  (1839)^* 
discussed  the  structural  control  of  the  Mohawk,  the 
Ohio,  and  the  Mississippi,  and  Lieutenant  Warren 
(1859)1^  concluded  that  the  Niobrara  must  have  orig- 
inated in  a  fissure.  According  to  Lesley  (1862)^^ 
the  course  of  the  New  River  across  the  Great  Val- 
ley and  into  the  Appalachians  '^striking  the  escarp- 
ment in  the  face"  is  determined  by  the  junction  of 
anticlinal  structures  on  the  north  with  faulted  mono- 
clines toward    the    south;     a    conclusion    in    harmony 


128  A  CENTUEY  OF  SCIENCE 

with  the  views  of  Edward  Hitchcock  (1841)^^  that  major 
valleys  and  mountain  passes  are  structural  in  origin  and 
that  even  subordinate  folds  and  faults  may  determine 
minor  features.  ^*Is  not  this  a  beautiful  example  of 
prospective  benevolence  on  the  part  of  the  Deity,  thus, 
by  means  of  a  violent  fracture  of  primary  moun- 
tains, to  provide  for  easy  intercommunication  through 
alpine  regions,  countless  ages  afterwards ! '  ^  The  extent 
of  the  wandering  from  the  guidance  of  DeSaussure  and 
Playfair  after  the  lapse  of  50  years  is  shown  by  students 
of  Switzerland.  Alpine  valleys  to  Murchison  (1851) 
were  bays  of  an  ancient  sea;  Schlaginweit  (1852)  found 
regional  and  local  complicated  crustal  movements  a  satis- 
factory cause,  and  Forbes  (1863)  saw  only  glaciers. 

Valleys  Formed  hy  Mivers, 

One  strong  voice  before  1860  appears  to  have  called 
Americans  back  to  truths  expounded  by  Desmarest  and 
Hutton.  Dana  in  1850^^  amply  demonstrated  that  val- 
leys on  the  Pacific  Islands  owe  neither  their  origin, 
position  or  form  to  the  sea  or  to  structural  factors. 
They  are  the  work  of  existing  streams  which  have  eaten 
their  way  headwards.  Even  the  valleys  of  Australia 
cited  by  Darwin  as  type  examples  of  ocean  work  are 
shown  to  be  products  of  normal  stream  work.  Dana 
went  further  and  gave  a  permanent  place  to  the  Hut- 
tonian  idea  that  many  bays,  inlets,  and  fiords  are  but  the 
drowned  mouths  of  stream-made  valleys.  In  the  same 
volume  in  which  these  conclusions  appeared,  Hubbard 
(1850)^^  announced  that  in  New  Hampshire  the  **  deepest 
valleys  are  but  valleys  of  erosion."  The  theory  that 
valleys  are  excavated  by  streams  which  occupy  them 
was  all  but  universally  accepted  after  F.  V.  Hayden's 
description^^  of  Rocky  Mountain  gorges  (1862)  and  New- 
berry's interpretation  of  the  canyons  of  Arizona  (1862) ; 
but  the  scientific  world  was  poorly  prepared  for  New- 
berry's statement -.2^ 

''Like  the  great  canons  of  the  Colorado,  the  broad  valleys 
bounded  by  high  and  perpendicular  walls  belong  to  a  vast  system 
of  erosion,  and  are  wholly  due  to  the  action  of  water.  .  .  .  The 
first  and  most  plausible  explanation  of  the  striking  surface  fea- 
tures of  this  region  will  be  to  refer  them  to  that  embodiment  of 


INTERPRETATION  OF  LAND  FORMS       129 

resistless  power — the  sword  that  cuts  so  many  geological  knots — • 
volcanic  force.  The  Great  Caiion  of  the  Colorado  would  be 
considered  a  vast  fissure  or  rent  in  the  earth's  crust,  and  the 
abrupt  termination  of  the  steps  of  the  table  lands  as  marking 
lines  of  displacement.  This  theory  though  so  plausible,  and  so 
entirely  adequate  to  explain  all  the  striking  phenomena,  lacks 
a  single  requisite  to  acceptance,  and  that  is  truth/* 

With  such  stupendous  examples  in  mind,  the  dictum 
of  Hutton  seemed  reasonable :  ''there  is  no  spot  on  which 
rivers  may  not  formerly  have  run.'' 

Denudation  by  Mivers, 

The  general  recognition  of  the  competency  of  streams 
to  form  valleys  was  a  necessary  prelude  to  the  broader 
view  expressed  by  Jukes  (1862)^^ 

''The  surfaces  of  our  present  lands  are  as  much  carved  and 
sculptured  surfaces  as  the  medallion  carved  from  the  slab,  or  the 
statue  sculptured  from  the  block.  They  have  been  gradually 
reached  by  the  removal  of  the  rock  that  once  covered  them,  and 
are  themselves  but  of  transient  duration,  always  slowly  wasting 
from  decay." 

Contributions  to  the  Journal  between  1850  and  1870 
reveal  a  tendency  to  accept  greater  degrees  of  erosion 
by  rivers,  but  the  necessary  end-product  of  subaerial 
erosion — a  plain — is  first  clearly  defined  by  Powell  in 
1875.^^  In  formulating  his  ideas  Powell  introduced  the 
term  "base-level,''  which  may  be  called  the  germ  word 
out  of  which  has  grown  the  "cycle  of  erosion,"  the 
master  key  of  modern  physiographers.  The  original 
definition  of  base-level  follows: 

"We  may  consider  the  level  of  the  sea  to  be  a  grand  base- 
level,  below  which  the  dry  lands  cannot  be  eroded ;  but  we  may 
also  have,  for  local  and  temporary  purposes,  other  base-levels  of 
erosion,  which  are  the  levels  of  the  beds  of  the  principal  streams 
which  carry  away  the  products  of  erosion.  (I  take  some  liberty 
in  using  the  term  'level'  in  this  connection,  as  the  action  of  a 
running  stream  in  wearing  its  channel  ceases,  for  all  practical 
purposes,  before  its  bed  has  quite  reached  the  level  of  the  lower 
end  of  the  stream.  What  I  have  called  the  base-level  would,  in 
fact,  be  an  imaginary  surface,  inclining  slightly  in  all  its  parts 
toward  the  lower  end  of  the  principal  stream  draining  the  area 


130  A  CENTURY  OF  SCIENCE 

through  which  the  level  is  supposed  to  extend,  or  having  the 
inclination  of  its  parts  varied  in  direction  as  determined  by 
tributary  streams.) " 

Analysis  of  Powell's  view  has  given  definiteness  to  the 
distinction  between  ** base-level/'  an  imaginary  plane, 
and  '*a  nearly  featureless  plain,"  the  actual  land  surface 
produced  in  the  last  stage  of  subaerial  erosion. 

Following  their  discovery  in  the  Colorado  Plateau 
Province,  denudation  surfaces  were  recognized  on  the 
Atlantic  slope  and  discussed  by  McGee  ( 1888)  j'-"^  in  a  paper 
notable  for  the  demonstration  of  the  use  of  physiographic 
methods  and  criteria  in  the  solution  of  stratigraphic 
problems.  Davis  (1889)^^  described  the  upland  of 
southern  New  England  developed  during  Cretaceous 
time,  introducing  the  term  ^* peneplain,''  '*a  nearly  fea- 
tureless plain."  The  short-lived  opposition  to  the 
theory  of  peneplanation  indicates  that  in  America  at  least 
the  idea  needed  only  formulation  to  insure  acceptance. 

It  is  interesting  to  note  that  surfaces  now  classed  as 
peneplains  were  fully  described  by  Percival  (1842),^^ 
who  assigned  them  to  structure,  and  by  Kerr  (1880),^'^ 
who  considered  glaciers  the  agent.  In  Europe  **  plains 
of  denudation"  have  been  clearly  recognized  by  Ramsay 
(1846),  Jukes  (1862),  A.  Geikie  (1865),  Foster  and  Top- 
ley  (1865),  Maw  (1866),  Wynne  (1867),  Whitaker  (1867), 
Macintosh  (1869),  Green  (1882),  Richthofen  (1882),  but 
all  of  them  were  looked  upon  as  products  of  marine  work, 
and  writers  of  more  recent  date  in  England  seem  reluc- 
tant to  give  a  subordinate  place  to  the  erosive  power  of 
waves.  Americans,  on  the  other  hand,  have  been  think- 
ing in  terms  of  rivers,  and  the  great  contribution  of  the 
American  school  is  not  that  peneplains  exist,  but  that 
they  are  the  result  of  normal  subaerial  erosion.  More 
precise  field  methods  during  the  past  decade  have 
revealed  the  fact  that  no  one  agent  is  responsible  for  the 
land  forms  classed  as  peneplains;  that  not  only  rivers 
and  ocean,  but  ice,  wind,  structure,  and  topographic 
position  must  be  taken  into  account. 

The  recognition  of  rivers  as  valley-makers  and  of  the 
final  result  of  stream  work  necessarily  preceded  an 
analysis  of  the  process  of  subaerial  erosion.     The  first 


INTERPRETATION  OF  LAND  FORMS       131 

and  last  terms  were  known,  the  intermediate  terms  and 
the  sequence  remained  to  be  established.  A  significant 
contribution  to  this  problem  was  made  by  Jukes  {1862).^^ 

"...  I  believe  that  the  lateral  valleys  are  those  which  were 
first  formed  by  the  drainage  running  directly  from  the  crests  of 
the  chains,  the  longitudinal  ones  being  subsequently  elaborated 
along  the  strike  of  the  softer  or  more  erodable  beds  exposed  on 
the  flanks  of  those  chains. ' ' 

PowelPs  discussion  of  antecedent  and  consequent 
drainage  (1875)  and  Gilbert's  chapter  on  land  sculpture 
in  the  Henry  Mountain  report  (1880)  are  classics,  and 
McGee's  contribution^^  contains  significant  suggestions. 
but  the  master  papers  are  by  Davis,^'^  who  introduces  an 
analysis  of  land  forms  based  on  structure  and  age  by  the 
statement : 

"Being  fully  persuaded  of  the  gradual  and  gystematic  evolu- 
tion of  topographical  forms  it  is  now  desired  ...  to  seek  the 
causes  of  the  location  of  streams  in  their  present  courses ;  to  go 
back  if  possible  to  the  early  date  when  central  Pennsylvania  was 
first  raised  from  the  sea,  and  trace  the  development  of  the  several 
river  systems  then  implanted  upon  it  from  their  ancient  begin- 
ning to  the  present  time." 

That  such  a  task  could  have  been  undertaken  a  quarter 
of  a  century  ago  and  to-day  considered  a  part  of  every- 
day field  work  shows  how  completely  the  lost  ground  of  a 
half-century  has  been  regained  and  how  rapid  the 
advance  in  the  knowledge  of  land  sculpture  since  the 
canyons  of  the  Colorado  Plateau  were  interpreted. 

Features  Resulting  from  Glaciation, 

The  Problem  Stated, 

Early  in  the  nineteenth  century  when  speculation 
regarding  the  interior  of  the  earth  gave  place  in  part  to 
observations  of  the  surface  of  the  earth,  geologists  were 
confronted  with  perhaps  the  most  difficult  problem  in  the 
history  of  the  science.  As  stated  by  the  editor  of  the 
Journal  in  1821 :3« 

''The  almost  universal  existence  of  rolled  pebbles,  and  boulders 
of  rock,  not  only  on  the  margin  of  the  oceans,  seas,  lakes,  and 
rivers;    but  their  existence,   often  in  enormous  quantities,   in 


132  A  CENTURY  OF  SCIENCE 

situations  quite  removed  from  large  waters;  inland, — ^in  high 
banks,  imbedded  in  strata,  or  scattered,  occasionally,  in  pro- 
fusion, on  the  face  of  almost  every  region,  and  sometimes  on  the 
tops  and  declivities  of  mountains,  as .  well  as  in  the  vallies 
between  them;  their  entire  difference,  in  many  cases,  from  the 
rocks  in  the  country  where  they  lie — rounded  masses  and  peb- 
bles of  primitive  rocks  being  deposited  in  secondary  and  alluvial 
regions,  and  vice  versa;  these  and  a  multitude  of  similar  facts 
have  ever  struck  us  as  being  among  the  most  interesting  of 
geological  occurrences,  and  as  being  very  inadequately  accounted 
for  by  existing  theories. ' ' 

The  phenomena  demanding  explanation  —  jumbled 
masses  of  *^ diluvium,"  polished  and  striated  rock, 
bowlders  distributed  with  apparent  disregard  of  topog- 
raphy— were  indeed  startling.  Even  Lyell,  the  great 
exponent  of  uniformitarianism,  appears  to  have  lost  faith 
in  his  theories  when  confronted  with  facts  for  which 
known  causes  seemed  inadequate.  The  interest  aroused 
is  attested  by  31  titles  in  the  Journal  during  its  first  two 
decades,  articles  which  include  speculations  unsupported 
by  logic  or  fact,  field  observation  unaccompanied  by- 
explanation,  field  observation  with  fantastic  explanation, 
ex-cathedra  pronouncements  by  prominent  men,  sound 
reasoning  from  insufficient  data,  and  unclouded  recogni- 
tion of  cause  and  effect  by  both  obscure  and  prominent 
men.  With  little  knowledge  of  glaciers,  areal  geology, 
or  of  structure  and  composition  of  drift,  all  known  forces 
were  called  in:  normal  weathering,  catastrophic  floods, 
ocean  currents,  waves,  icebergs,  glaciers,  wind,  and  even 
depositions  from  a  primordial  atmosphere  (Chabier, 
1823).  Human  agencies  were  not  discarded.  Speak- 
ing of  a  granite  bowlder  at  North  Salem,  New  York, 
described  by  Cornelius  (1820)^^  as  resting  on  limestone, 
Finch  (1824)^2  says:  '4t  is  a  magnificent  cromlech  and 
the  most  ancient  and  venerable  monument  which  America 
possesses."  In  the  absence  of  a  known  cause,  cata- 
strophic agencies  seem  reasonable. 

The  Deluge, 

In  the  seventh  volume  of  the  Journal  (1824)^^  we  read: 

''After  the  production  of  these  regular  strata  of  sand,  clay, 
limestone,  &c.  came  a  terrible  irruption  of  water  from  the  north, 


INTERPRETATION  OF  LAND  FORMS       133 

or  north-west,  which  in  many  places  covered  the  preceding 
formations  with  diluvial  gravel,  and  carried  along  with  it  those 
immense  masses  of  granite,  and  the  older  rocks,  which  attest  to 
the  present  day  the  destruction  and  ruin  of  a  former  world." 

Another  author  remarks : 

' '  We  find  a  mantle  as  it  were  of  sand  and  gravel  indifferently 
covering  all  the  solid  strata,  and  evidently  derived  from  some 
convulsion  which  has  lacerated  and  partly  broken  up  those 
strata.  ..." 

The  catastrophe  favored  by  most  geologists  was  floods 
of  water  violently  released — *^we  believe,"  says  the 
editor,  ^^that  all  geologists  agree  in  imputing  .  .  .  the 
diluvium  to  the  agency  of  a  deluge  at  one  period  or 
another."^*  Such  conclusions  rested  in  no  small  way 
upon  Hayden's  well-known  treatise  on  surficial  deposits 
(1821),^^  a  volume  which  deserves  a  prominent  place  in 
American  geological  literature.  Hayden  clearly  dis- 
tinguished the  topographic  and  structural  features  of  the 
drift  but  found  an  adequate  cause  in  general  wide-spread 
currents  which  **  flowed  impetuously  across  the  whole 
continent . . .  from  north  east  to  south  west."  In  review- 
ing Hayden 's  book  Silliman  remarks: 

* '  The  general  cause  of  these  currents  Mr.  Hayden  concludes  to 
be  the  deluge  of  Noah.  While  no  one  will  object  to  the  propriety 
of  ascribing  very  many,  probably  most  of  our  alluvial  features, 
to  that  catastrophe,  we  conceive  that  neither  Mr.  Hayden,  nor 
any  other  man,  is  bound  to  prove  the  immediate  physical  cause 
of  that  vindictive  infliction. 

We  would  beg  leave  to  suggest  the  following  as  a  cause  which 
may  have  aided  in  deluging  the  earth,  and  which,  were  there 
occasion,  might  do  it  again. 

The  existence  of  enormous  caverns  in  the  bowels  of  the  earth, 
(so  often  imagined  by  authors,)  appears  to  be  no  very  extrava- 
gant assumption.  It  is  true  it  cannot  be  proved,  but  in  a  sphere 
of  eight  thousand  miles  in  diameter,  it  would  appear  in  no  way 
extraordinary,  that  many  cavities  might  exist,  which  collectively, 
or  even  singly,  might  well  contain  much  more  than  all  our 
oceans,  seas,  and  other  superficial  waters,  none  of  which  are 
probably  more  than  a  few  miles  in  depth.  If  these  cavities  com- 
municate in  any  manner  with  the  oceans,  and  are  (as  if  they 
exist  at  all,  they  probably  are,)  filled  with  water,  there  exist,  we 


134  A  CENTURY  OF  SCIENCE 

conceive,  agents  very  competent  to  expel  the  water  of  these  cav- 
ities, and  thus  to  deluge,  at  any  time,  the  dry  land. ' ' 

The  teachings  of  Hayden  were  favorably  received  by 
Hitchcock,  Struder,  and  Hubbard,  and  many  Europeans. 
They  found  a  champion  in  Jackson,  who  states  (1839)  :^^ 

'^From  the  observations  made  upon  Mount  Ktaadn,  it  is 
proved,  that  the  current  did  rush  over  the  summit  of  that  lofty 
mountain,  and  consequently  the  diluvial  waters  rose  to  the  height 
of  more  than  5,000  feet.  Hence  we  are  enabled  to  prove,  that  the 
ancient  ocean,  which  rushed  over  the  surface  of  the  State,  was  at 
least  a  mile  in  depth,  and  its  transporting  power  must  have 
been  greatly  increased  by  its  enormous  pressure. ' ' 

Gibson,  a  student  of  western  geology,  reaches  the  same 
conclusion  (1836)  :^^ 

*'That  a  wide-spread  current,  although  not,  as  imagined,  fed 
from  an  inland  sea,  once  swept  over  the  entire  region  between 
the  Alleghany  and  the  Rocky  Mountains  is  established  by 
plenary  proof." 

Professor  Sedgwick  (1831)  thought  the  sudden  up- 
heaval of  mountains  sufficient  to  have  caused  floods 
again  and  again.  The  strength  of  the  belief  in  the  Bib- 
lical flood,  during  the  first  quarter  of  the  19th  century, 
may  be  represented  by  the  following  remarks  of  Phil- 
lips (1832)  :38 

''Of  many  important  facts  which  come  under  the  consideration 
of  geologists,  the  'Deluge'  is,  perhaps,  the  most  remarkable;  and 
it  is  established  by  such  clear  and  positive  arguments,  that  if  any 
one  point  of  natural  history  may  be  considered  as  proved,  the 
deluge  must  be  admitted  to  have  happened,  because  it  has  left 
full  evidence  in  plain  and  characteristic  effects  upon  the  surface 
of  the  earth/' 

However,  the  theory  of  deluges,  whether  of  ocean  or 
land  streams,  did  not  hold  the  field  unopposed.  In  1823, 
Granger,^^  an  observer  whose  contributions  to  science 
total  only  six  pages,  speaks  of  the  striae  on  the  shore  of 
Lake  Erie  as 

"having  been  formed  by  the  powerful  and  continued  attrition  of 
some  hard  body.  ...  To  me,  it  does  not  seem  possible  that  water 
under  any  circumstances,  could  have  effected  it.     The  flutings  in 


INTERPEETATION  OF  LAND  FORMS       135 

width,  depth,  and  direction,  are  as  regular  as  if  they  had  been 
cut  out  by  a  grooving  plane.  This,  running  water  could  not 
effect,  nor  could  its  operation  have  produced  that  glassy  smooth- 
ness, which,  in  many  parts,  it  still  retains." 

Hayes  and  also  Conrad  expressed  similar  views  in  the 
Journal  16  years  later. 

The  idea  that  ice  was  in  some  way  concerned  with  the 
transportation  of  drift  has  had  a  curious  history.  The 
first  unequivocal  statement,  based  on  reading  and  keen 
observation,  was  made  in  the  Journal  by  Dobson  in 
1826  :*« 

**I  have  had  occasion  to  dig  up  a  great  number  of  bowlders,  of 
red  sandstone,  and  of  the  conglomerate  kind,  in  erecting  a  cotton 
manufactory;  and  it  was  not  uncommon  to  find  them  worn 
smooth  on  the  under  side,  as  if  done  by  their  having  been 
dragged  over  rocks  and  gravelly  earth,  in  one  steady  position. 
On  examination,  they  exhibit  scratches  and  furrows  on  the 
abraded  part;  and  if  among  the  minerals  composing  the  rock, 
there  happened  to  be  pebbles  of  feldspar,  or  quartz,  (which  was 
not  uncommon,)  they  usually  appeared  not  to  be  worn  so  much 
as  the  rest  of  the  stone,  preserving  their  more  tender  parts  in  a 
ridge,  extending  some  inches.  When  several  of  these  pebbles 
happen  to  be  in  one  block,  the  preserved  ridges  were  on  the  same 
side  of  the  pebbles,  so  that  it  is  easy  to  determine  which  part  of 
the  stone  moved  forward,  in  the  act  of  wearing. 

These  bowlders  are  found,  not  only  on  the  surface,  but  I  have 
discovered  them  a  number  of  feet  deep,  in  the  earth,  in  the  hard 
compound  of  clay,  sand,  and  gravel.  .  .  . 

I  think  we  cannot  account  for  these  appearances,  unless  we 
call  in  the  aid  of  ice  along  with  water,  and  that  they  have  been 
worn  by  being  suspended  and  carried  in  ice,  over  rocks  and 
earth,  under  water." 

In  Dobson 's  day  the  hypothesis  of  ** gigantic  floods," 
*^ debacles,"  ^^ resistless  world-wide  currents,"  was  so 
firmly  entrenched  that  the  voice  of  the  observant  layman 
found  no  hearers,  and  a  letter  from  Dobson  to  Hitchcock 
written  in  1837  and  containing  additional  evidence  and 
argument  remained  unpublished  until  Murchison,  in 
1842,^1  paid  his  respects  to  the  remarkable  work  of  a 
remarkable  man.* 

*  Peter  Dobson  (1784-1878)  came  to  this  country  from  Preston,  England, 
in  1809  and  established  a  cotton  factory  at  Vernon,  Conn. 


136  A  CENTURY  OF  SCIENCE 

'  *  I  take  leave  of  the  glacial  theory  in  congratulating  American 
science  in  having  possessed  the  original  author  of  the  best 
glacial  theory,  though  his  name  had  escaped  notice;  and  in 
recommending  to  you  the  terse  argument  of  Peter  Dobson,  a 
previous  acquaintance  with  which  might  have  saved  volumes  of 
disputation  on  both  sides  of  the  Atlantic." 

Glaciers  vs.  Icebergs, 

The  glacial  theory  makes  its  way  into  geological  lit- 
erature with  the  development  of  Agassiz  (1837)  of  the 
views  of  Venetz  (1833)  and  Charpentier  (1834),  that  the 
glaciers  of  the  Alps  once  had  greater  extent.  The  bold 
assumption  was  made  that  the  surface  of  Europe  as  far 
south  as  the  shores  of  the  Mediterranean  and  Caspian 
seas  was  covered  by  ice  during  a  period  immediately 
preceding  the  present.  The  kernel  of  the  present  gla- 
cial theory  is  readily  recognizable  in  these  early  works, 
but  it  is  wrapped  in  a  strange  husk :  it  was  assumed  that 
the  Alps  were  raised  by  a  great  convulsion  under  the 
ice  and  that  the  erratics  slid  to  their  places  over  the 
newly  made  declivities.  The  publication  of  the  famous 
^* Etudes  sur  les  Glaciers"  (1840),  remarkable  alike  for 
its  clarity,  its  sound  inductions,  and  wealth  of  illustra- 
tions, brought  the  ideas  of  Agassiz  more  into  prominence 
and  inaugurated  a  30-years'  war  with  the  proponents  of 
currents  and  icebergs.  The  outstanding  objections  to  the 
theory  were  the  requirement  of  a  frigid  climate  and  the 
demand  for  glaciers  of  continental  dimensions;  very 
strong  objections,  indeed,  for  the  time  when  fossil  evi- 
dence was  not  available,  the  great  polar  ice  sheets  were 
unexplored,  and  the  distinction  between  till  and  water- 
laid  drift  had  not  been  established. 

The  glacial  theory  was  cordially  adopted  by  Buck- 
land  (1841)*^  and  in  part  by  Lyell  in  England  but 
viewed  with  suspicion  by  Sedgwick,  Whewell,  and  Man- 
tell.  In  America  the  response  to  the  new  idea  was 
immediate.  Hitchcock  (1841)^*^  concludes  an  able  dis- 
cussion with  the  statement:  *'So  remarkably  does  it 
solve  most  of  the  phenomena  of  diluvial  action,  that  I  am 
constrained  to  believe  its  fundamental  principles  to  be 
founded  in  truth. ' ' 

The  theory  formed  the  chief  topic  of  discussion  at  the 


INTERPEETATION  OF  LAND  FORMS       137 

third  and  fourth  meetings  of  the  Association  of  American 
Geologists  and  Naturalists  (1842,  1843)  under  the  lead 
of  a  committee  on  drift  consisting  of  Emmons,  W.  B. 
Rogers,  Vanuxem,  Nicollet,  Jackson,  and  J.  L.  Hayes. 
The  result  of  these  discussions  was  a  curious  reaction. 
Hitchcock  complained  that  he  **had  been  supposed  to  be 
an  advocate  for  the  unmodified  glacial  theory,  but  he  had 
never  been  a  believer  in  it,''  and  Jackson  spoke  for  a 
number  of  men  when  he  stated:*^ 

*'This  country  exhibits  no  proofs  of  the  glacial  theory  as  taught 
by  Agassiz  but  on  the  contrary  the  general  bearing  of  the  facts 
is  against  that  theory.  .  .  .  Many  eminent  men  incautiously 
embraced  the  new  theory,  which  within  two  or  three  years  from 
its  promulgation,  had  been  found  utterly  inadequate,  and  is  now 
abandoned  by  many  of  its  former  supporters.'' 

Out  of  this  symposium  came  also  the  strange  contribu- 
tion of  H.  D.  Rogers  (1844),**  who  cast  aside  the  teach- 
ings of  deduction  and  observation  and  returned  to  the 
views  of  the  Medievalists. 

* '  If  we  will  conceive,  then,  a  wide  expanse  of  waters,  less  per- 
haps than  one  thousand  feet  in  depth,  dislodged  from  some  high 
northern  or  circumpolar  basin,  by  a  general  lifting  of  that  region 
of  perhaps  a  few  hundred  feet,  and  an  equal  subsidence  of  the 
country  south,  and  imagine  this  whole  mass  converted  by  earth- 
quake pulsations  of  the  breadth  which  such  undulations  have, 
into  a  series  of  stupendous  and  rapid-moving  waves  of  transla- 
tion, helped  on  by  the  still  more  rapid  flexures  of  the  floor  over 
which  they  move,  and  then  advert  to  the  shattering  and  loosen- 
ing power  of  the  tremendous  jar  of  the  earthquake,  we  shall  have 
an  agent  adequate  in  every  way  to  produce  the  results  we  see,  to 
float  the  northern  ice  from  its  moorings,  to  rip  off,  assisted  with 
its  aid,  the  outcrops  of  the  hardest  strata,  to  grind  up  and  strew 
wide  their  fragments,  to  scour  down  the  whole  rocky  floor,  and, 
gathering  energy  with  resistance,  to  sweep  up  the  slopes  and  over 
the  highest  mountains." 

Because  of  the  prominence  of  their  author,  Rogers's 
views  exerted  some  influence  and  seemingly  received 
support  from  England  through  the  elaborate  mathematic 
discussions  of  Whewell  (1848),  who  considered  the  drift 
as  *  irresistible  proof  of  paroxysmal  action,"  and  Hop- 
kins (1852),  who  contended  for  *^  currents  produced  by 
repeated  elevatory  movements." 


138  A  CENTURY  OF  SCIENCE 

After  his  arrival  in  America  (1846),  Agassiz's  influ- 
ence was  felt,  and  his  paper  on  the  erratic  phenomena 
about  Lake  Superior  (1850),^^  in  which  he  called  upon 
the  advocates  of  water-borne  ice  to  point  out  the  barrier 
which  caused  the  current  to  subside,  produced  a  salu- 
tary effect;  yet  Desor  (1852)^^  states  that  in  the  region 
described  by  Agassiz  ^^the  assumption  [of  a  general  ice 
cap]  is  no  longer  admissible, ^ ^  and  that  the  bowlders  on 
Long  Island  *Svere  transported  on  ice  rafts  along  the  sea 
shore  and  stranded  on  the  ridges  and  eminences  which 
were  then  shoals  along  the  coast.''  Twenty  years  of 
discussion  were  insufficient  to  establish  the  glacial  theory 
either  in  Europe  or  America.  The  consensus  of  opinion 
among  the  more  advanced  thinkers  in  1860  is  expressed 
by  Dana  i^"^ 

*'In  view  of  the  whole  subject,  it  appears  reasonable  to  con- 
clude that  the  Glacier  theory  affords  the  best  and  fullest 
explanation  of  the  phenomena  over  the  general  surface  of  the 
continents,  and  encounters  the  fewest  difficulties.  But  icebergs 
have  aided  beyond  doubt  in  producing  the  results  along  the 
borders  of  the  continents,  across  ocean-channels  like  the  German 
Ocean  and  the  Baltic,  and  possibly  over  great  lakes  like  those  of 
North  America.  Long  Island  Sound  is  so  narrow  that  a  glacier 
may  have  stretched  across  it." 

Papers  in  the  Journal  of  1860-70  show  a  prevailing 
belief  in  icebergs,  but  the  evidence  for  land  ice  was 
accumulating  as  the  deposits  became  better  known,  and 
in  1871  field  workers  speak  in  unmistakable  tones  :^^ 

*'It  is  still  a  mooted  question  in  American  geology  whether  the 
events  of  the  Glacial  era  were  due  to  glaciers  or  icebergs.  .  .  . 
American  geologists  are  still  divided  in  opinion,  and  some  of  the 
most  eminent  have  pronounced  in  favor  of  icebergs. 

Since,  then,  icebergs  cannot  pick  up  masses  tons  in  weight 
from  the  bottom  of  a  sea,  or  give  a  general  movement  southward 
to  the  loose  material  of  the  surface;  neither  can  produce  the 
abrasion  observed  over  the  rocks  under  its  various  conditions; 
and  inasmuch  as  all  direct  evidence  of  the  submergence  of  the 
land  required  for  an  iceberg  sea  over  New  England  fails,  the 
conclusion  appears  inevitable  that  icebergs  had  nothing  to  do 
with  the  drift  of  the  New  Haven  region,  in  the  Connecticut 
valley ;  and,  therefore,  that  the  Glacial  era  in  central  New  Eng- 
land was  a  Glacier  era." 


INTERPEETATION  OF  LAND  FORMS       139 

Matthew  (1871)^^  reached  the  same  conclusion  for  the 
Lower  Provinces  of  Canada.  In  spite  of  the  increasing 
clarity  of  the  evidence,  the  battle  for  the  glacial  theory 
was  not  yet  won.  The  remaining  opponents  though  few 
in  number  were  distinguished  in  attainments.  Dawson 
clung  to  the  outworn  doctrine  until  his  death  in  1899. 

An  interesting  feature  of  the  history  of  glacial  theories 
is  the  calculation  by  Maclaren  (1842)^^  that  the  amount 
of  water  abstracted  from  the  seas  to  form  the  hypo- 
thetical ice  sheet  would  lower  the  ocean-level  350  feet — • 
an  early  form  of  the  glacial  control  hypothesis  (see 
Daly^O. 

Extent  of  Glacial  Drift, 

By  the  middle  of  the  nineteenth  century,  it  was  recog- 
nized that  the  ^* drift,"  whatever  its  origin,  was  not  of 
world-wide  extent.  In  America  its  characteristic  features 
were  found  best  developed  north  of  latitude  40  degrees; 
in  Europe,  the  Alps,  the  Scottish  Highlands,  and  Scandi- 
navia were  recognized  as  type  areas.  The  limits  were 
unassigned,  partly  because  the  field  had  not  been  sur- 
veyed, but  largely  because  criteria  for  the  recognition  of 
drift  had  not  been  established.  The  well-known  hillocks 
and  ridges  of  ** diluvium"  and  '* alluvium"  and  *^ drift" 
of  New  Jersey  and  Ohio,  and  the  mounds  of  the  Missouri 
Cotou  elaborately  described  by  Catlin  (1840)^^  bore 
little  resemblance  to  the  walls  of  unsorted  rock  which 
stand  as  moraines  bordering  Alpine  glaciers.  The 
Orange  sand  of  Mississippi  was  included  in  the  drift  by 
Hilgard  (1866),^^  and  the  gravels  at  Philadelphia  by 
Hall  (1876).^*  Stevens  (1873)^^  described  trains  of  gla- 
cial erratics  at  Richmond,  Virginia,  and  William  B. 
Rogers  (1876)^^  accounts  for  certain  deposits  in  the  Poto- 
mac, James,  and  Roanoke  rivers  by  the  presence  of 
Pleistocene  ice  tongues  or  swollen  glacial  rivers,  and 
remarks:  *^It  is  highly  probable  that  glacial  action  had 
much  to  do  with  the  original  accumulation  of  the  rocky 
debris  on  the  flanks  of  the  Blue  Ridge,  and  in  the  Appa- 
lachian valleys  beyond."  Kerr  (1881)^"^  referred  the 
ancient  erosion  surface  of  the  Piedmont  belt  in  North 
Carolina  to  glacial  denudation,  De  la  Beche  compared 


140  A  CENTURY  OF  SCIENCE 

the  drift  of  Jamaica  with  that  of  New  England,  and 
Agassiz  interpreted  soils  of  Brazil  as  glacial. 

The  first  detailed  description  and  unequivocal  inter- 
pretation of  either  terminal  or  recessional  moraines  is 
from  the  pen  of  Gilbert  (1871),^^  geologist  of  the  Ohio 
Survey.  In  discussing  the  former  outlet  of  Lake  Erie 
through  the  Fort  Wayne  channel,  Gilbert  writes : 

''The  page  of  history  recorded  in  these  phenomena  is  by  no 
means  ambiguous.  The  ridges,  or,  more  properly,  the  ridge 
which  determines  the  courses  of  the  St.  Joseph  and  St.  Marys 
rivers  is  a  buried  terminal  moraine  of  the  glacier  that  moved 
south  west  ward  through  the  Maumee  valley.  The  overlying  Erie 
Clay  covers  it  from  sight,  but  it  is  shadowed  forth  on  the  surface 
of  that  deposit,  as  the  ground  is  pictured  through  a  deep  and 
even  canopy  of  snow.  Its  irregularly  curved  outline  accords 
intimately  with  the  configuration  of  the  valley,  and  with  the 
direction  of  the  ice  markings;  its  concavity  is  turned  toward 
the  source  of  motion ;  its  greatest  convexity  is  along  the  line  of 
least  resistance. 

South  of  the  St.  Marys  river  are  other  and  numerous  moraines 
accompanied  by  glacial  striae.  Their  character  and  courses 
have  not  yet  been  studied ;  but  their  presence  carries  the  mind 
back  to  an  epoch  of  the  cold  period,  when  the  margin  of  the  ice- 
field was  farther  south,  and  the  glacier  of  the  Maumee  valley  was 
merged  in  the  general  mass.  As  the  mantle  of  ice  grew  shorter — 
and,  in  fact,  at  every  stage  of  its  existence — its  margin  must  have 
been  variously  notched  and  lobed  in  conformity  with  the  contour 
of  the  country,  the  higher  lands  being  first  laid  bare  by  the 
encroaching  secular  summer.  Early  in  the  history  of  this 
encroachment  the  glacier  of  the  Maumee  valley  constituted  one  of 
these  lobes,  and  has  recorded  its  form  in  the  two  moraines  that 
I  have  described. ' ' 

Three  years  after  the  recognition  of  moraines  in  the 
Maumee  valley,  Chamberlin  (1874)^^  showed  that  the 
seemingly  disorganized  mounds  and  basins  and  ridges 
known  as  the  Kettle  range  of  Wisconsin  is  the  terminal 
moraine  of  the  Green  Bay  glacier.  At  an  earlier  date 
(1864)  Whittlesey  interpreted  the  kettles  of  the  Wis- 
consin moraine  as  evidence  of  ice  blocks  from  a  melting 
glacier  and  presented  a  map  showing  the  ^*  southern 
limit  of  boulders  and  coarse  drift.''  In  1876  attention 
was  called  to  the  terminal  moraine  of  New  England  by  G. 


INTERPRETATION  OF  LAND  FORMS       141 

Frederick  Wright,  who  assigns  the  honor  of  discovery  to 
Clarence  King. 

With  the  observations  of  Gilbert,  Chamberlin,  and 
King  in  mind,  the  terminal  moraine  was  traced  by 
various  workers  across  the  United  States  and  into 
Canada  and  the  extent  of  glacial  cover  revealed.  Fol- 
lowing 1875  the  pages  of  the  Journal  contain  many  con- 
tributions dealing  with  the  origin  and  structure  of 
moraines,  eskers,  kames,  and  drumlins.  Before  1890 
twenty-eight  papers  on  the  glacial  phenomena  of  the  Erie 
and  Ohio  basin  alone  had  appeared.  By  1900  substantial 
agreement  had  been  reached  regarding  the  significant 
features  of  the  drift,  the  outline  history  of  the  Great 
Lakes  had  been  written,  and  the  way  had  been  paved  for 
stratigraphic  studies  of  the  Pleistocene,  which  bulk  large 
in  the  pages  of  the  Journal  for  the  last  two  decades. 

Epochs  of  Glaciation, 

For  a  decade  following  the  general  acceptance  of  the 
glacial  origin  of  *  diluvium,"  the  deposits  were  embraced 
as  **drift^'  and  treated  as  the  products  of  one  long  period 
of  glacial  activity,  and  throughout  the  controversy  of 
iceberg  and  glacier  the  unity  of  the  glacial  period  was 
unquestioned.  Beds  of  peat  and  fossiliferous  lacustrine 
deposits  in  Switzerland,  England,  and  in  America  and 
the  recognition  of  an  ** upper''  and  a  *4ower''  diluvium 
by  Scandinavian  geologists  suggested  two  epochs,  and  as 
the  examples  of  such  deposits  i^icreased  in  number  and 
it  became  evident  that  the  plant  fossils  represented  forms 
demanding  a  genial  climate  and  that  the  phenomena 
w^ere  seen  in  many  countries,  the  belief  grew  that  minor 
fluctuations  or  gradual  recession  of  an  ice  sheet  were 
inadequate  to  account  for  the  phenomena  observed. 

It  is  natural  that  this  problem  should  have  found  its 
solution  in  America,  where  the  Pleistocene  is  admirably 
displayed,  and  where  the  State  and  Federal  surveys  were 
actively  engaged  in  areal  mapping.  In  1883  Chamber- 
lin^^ presented  his  views  under  the  bold  title,  ^*  Prelim- 
inary Paper  on  the  Terminal  Moraine  of  the  Second 
Glacial  Epoch,''  and  the  existence  of  deposits  of  two  or 
more  ice  sheets  and  the  features  of  interglacial  periods 


142  A  CENTURY  OF  SCIENCE 

were  substantially  established  by  the  interesting  debate 
in  the  Journal  led  by  Chamberlin,  Wright,  Upham  and 
Dana.^^  Contributions  since  1895  have  been  concerned 
with  the  degree  rather  than  the  fact  of  complexity,  and 
continued  study  has  resulted  in  the  general  recognition 
of  five  glacial  stages  in  North  America  and  four  in 
Europe. 

The  Loess  as  a  Glacial  Deposit, 

A  curious  side-product  of  the  study  of  glaciation  in 
North  America  is  the  controversy  over  the  origin  of  loess. 
The  interest  aroused  is  indicated  by  scores  of  papers  in 
American  periodicals  and  State  reports  of  the  last  quar- 
ter of  the  19th  century — papers  which  bear  the  names  of 
prominent  geologists. 

The  ** loess"  in  the  valley  of  the  Rhine  had  long  been 
known,  but  the  subject  assumed  prominence  by  the  pub- 
lication in  1866  of  Pumpelly's  Travels  in  China.^^  Wide- 
spread deposits  200  to  1,000  feet  thick  were  described  as 
very  fine-grained  yellowish  earth  of  distinctive  structure 
without  stratification  but  penetrated  by  innumerable 
tubes  and  containing  land  or  fresh-water  shells,  Pum- 
pelly  considered  these  deposits  lacustrine,  a  view  which 
found  general  acceptance  though  combated  by  Kingsmill 
(1871),^^  who  argued  for  marine  deposition.  Baron  Von 
Richthofen^s  classic  on  China,  which  appeared  in  1877, 
amplifies  the  observations  of  Pumpelly  and  marshals  the 
evidence  to  support  the  hypothesis  that  the  loess  is  wind- 
laid  both  on  dry  land  and  within  ancient  salt  lakes.  The 
conclusions  of  Von  Richthofen  were  adopted  by  Pumpelly 
whose  knowledge  of  the  Chinese  deposits,  supplemented 
by  studies  in  Missouri,  of  which  State  he  was  director  of 
the  Geological  Survey  in  1872-73,  placed  him  in  position 
to  form  a  correct  judgment.     He  says  :^* 

''Recognizing  from  personal  observation  the  full  identity  of 
character  of  the  loess  of  northern  China,  Europe  and  the  Mis- 
souri Valley,  I  am  obliged  to  reject  my  own  explanation  of  the 
origin  of  the  Chinese  deposits,  and  to  believe  with  Richthofen 
that  the  true  loess,  wherever  it  occurs,  is  a  sub-aerial  deposit, 
formed  in  a  dry  central  region,  and  that  it  owes  its  structure  to 
the  formative  influence  of  a  steppe  vegetation. 

The  one  weak  point  of  Richthofen 's  theory  is  in  the  evident 


INTERPRETATION  OF  LAND  FORMS       143 

inadequacy  of  the  current  disintegration  as  a  source  of  material. 
When  we  consider  the  immense  area  covered  by  loess  to  depths 
varying  from  50  to  2,000  feet,  and  the  fact  that  this  is  only  the 
very  finest  portion  of  the  product  of  rock-destruction,  and  again 
that  the  accumulation  represents  only  a  very  short  period  of 
time,  geologically  speaking,  surely  we  must  seek  a  more  fertile 
source  of  supply  than  is  furnished  by  the  current  decomposition. 
of  rock  surface. 

It  seems  to  me  that  there  are  two  important  sources :  I.  The 
silt  brought  by  rivers,  many  of  them  fed  by  the  products  of 
glacial  attrition  flowing  from  the  mountains  into  the  central 
region.  Where  the  streams  sink  away,  or  where  the  lakes  which 
receive  them  have  dried  up,  the  finer  products  of  the  erosion 
of  a  large  territory  are  left  to  be  removed  in  dust  storms. 

II.  The  second  .  .  .  source  is  the  residuary  products  of  a 
secular  disintegration. ' ' 

The  evidence  presented  by  Pumpelly  for  the  eolian 
origin  of  loess — structure,  texture,  composition,  fossil 
content  and  topographic  position — is  complete,  and  to  him 
belongs  the  credit  for  the  correct  interpretation  of  the 
Mississippi  valley  deposits.  Unfortunately  his  contribu- 
tion came  at  a  time  when  the  geologists  of  the  central 
States  were  intent  on  tracing  the  paths  and  explaining 
the  work  of  Pleistocene  glaciers,  and  the  belief  was 
strong  that  loess  was  some  phase  of  glacial  work.  Its 
position  at  the  border  of  the  lowan  drift  so  obviously 
suggests  a  genetic  relation  that  the  fossil  evidence  of 
steppe  climate  suggested  by  Binney  in  1848^^  was  mini- 
mized. Students  of  Pleistocene  geology  in  Minnesota, 
Iowa,  Nebraska,  Missouri,  although  less  vigorous  in 
expression,  were  substantially  in  agreement  with  Hilgard 
(1879).^^  *^The  sum  total  of  anomalous  conditions 
required  to  sustain  the  eolian  hypothesis  partakes 
strongly' of  the  marvellous. '^  The  last  edition  of  Dana's 
Manual,  1894,  and  of  LeConte's  Geology,  1896,  the  two 
most  widely  used  text  books  of  their  time,  oppose  the 
eolian  theory,  and  Chamberlin,  in  1897,^"^  states:  **the 
aqueous  hypothesis  seems  best  supported  so  far  as  con- 
cerns the  deposits  of  the  Mississippi  Valley  and  western 
Europe"  (p.  795).  Shimek,  in  papers  published  since 
1896  has  shown  that  aquatic  and  glacial  conditions  can 
not  account  for  the  loess  fossils,  and  the  return  to  the 
views  of  Pumpelly  that  the  loess  was  deposited  on  land 


lU  A  CENTURY  OF  SCIENCE 

by  the  agency  of  wind  in  a  region  of  steppe  vegetation  is 
now  all  but  universal. 


Glacial  Sculpture, 

Within  the  present  generation  sculpture  by  glaciers  has 
received  much  attention  and  has  involved  a  reconsidera- 
tion of  the  ability  of  ice  to  erode  which  in  turn  involves 
a  crystallization  of  views  of  the  mechanics  of  moving  ice. 
The  evidence  for  glacier  erosion  has  remained  largely 
physiographic  and  rests  on  a  study  of  land  forms.  In 
fact,  the  inadequacy  of  structural  features  or  of  river 
corrasion  to  account  for  flat-floored,  steep-walled  gorges, 
hanging  valleys,  and  many  lake  basins,  rather  than  a 
knowledge  of  the  mechanics  of  ice  has  led  to  the  present 
fairly  general  belief  that  glaciers  are  powerful  agents  of 
rock  sculpture.  The  details  of  the  process  are  not  yet 
understood. 

Erosion  by  glaciers  enters  the  arena  of  active  discus- 
sion in  1862-63.  The  possibility  had  been  suggested  by 
Esmark  (1827)  and  by  Dana  (1849)  in  the  description  of 
fiords  and  by  Hind  (1855)  with  reference  to  the  origin 
of  the  Great  Lakes.  It  appears  full-fledged  in  Ramsay's 
classic,  which  was  published  simultaneously  in  England 
and  in  America.^^  The  argument  runs  as  follows: 
There  is  a  close  association  of  ancient  glaciers  and  lakes 
especially  in  mountains;  glaciers  are  amply  able  to 
erode;  evidences  of  faulting,  special  subsidence,  river 
erosion,  and  marine  erosion  are  absent  from  the  lake 
basins  of  Switzerland  and  Great  Britain.  To  quote 
Ramsay : 

*'It  required  a  solid  body  grinding  steadily  and  powerfully  in 
direct  and  heavy  contact  with  and  across  the  rocks  to  scoop  out 
deep  hollows,  the  situations  of  which  might  either  be  determined 
by  unequal  hardness  of  the  rocks,  by  extra  weight  of  ice 'in 
special  places,  or  by  accidental  circumstances,  the  clue  to  which 
is  lost  from  our  inability  perfectly  to  reconstruct  the  original 
forms  of  the  glaciers.'' 

'*I  believe  with  the  Italian  geologists,  that  all  that  the  glaciers 
as  a  whole  effected  was  only  slightly  to  deepen  these  valleys  and 
materially  to  modify  their  general  outlines,  and,  further  (a  the- 
ory I  am  alone  responsible  for),  to  deepen  them  in  parts  more 
considerably  when,  from  various  causes,  the  grinding  power  of 


INTERPRETATION  OF  LAND  FORMS       145 

the  ice  was  unusually  powerful,  especially  where,  as  in  the  low- 
lands of  Switzerland,  the  Miocene  strata  are  comparatively  soft/' 

Whittlesey  (1864)^^  considered  that  the  rock-bound 
lakes  and  narrow  bays  near  Lake  Superior  were  partly 
excavated  by  ice.  LeConte  (1875)^^  records  some  sig- 
nificant observations  in  a  pioneer  paper  on  glacier 
erosion  which  has  not  received  adequate  recognition. 
He  says: 

**...!  am  convinced  that  a  glacier,  by  its  enormous  pressure 
and  resistless  onward  movement,  is  constantly  breaking  off  large 
blocks  from  its  bed  and  bounding  walls.  Its  erosion  is  not  only  a 
grinding  and  scoring,  but  also  a  crushing  and  breaking.  It 
makes  by  its  erosion  not  only  rock-meal,  but  also  large  rock- 
chips.  ...  Its  erosion  is  a  constant  process  of  alternate  rough 
hewing  and  planing. 

If  Yosemite  were  unique,  we  might  suppose  that  it  was 
formed  by  violent  cataclysms;  but  Yosemite  is  not  unique  in 
form  and  therefore  probably  not  in  origin.  There  are  many 
Yosemites.  It  is  more  philosophical  to  account  for  them  by  the 
regular  operation  of  known  causes.  I  must  believe  that  all  these 
deep  perpendicular  slots  have  been  sawn  out  by  the  action  of  gla- 
ciers ;  the  peculiar  verticahty  of  the  walls  having  been  determined 
by  the  perpendicular  cleavage  structure.'*  ...  A  lake  in  Bloody 
Canyon  "is  a  pure  rock  basin  scooped  out  by  the  glacier  at  this 
place.  .  .  .  These  ridges  [separating  Hope,  Faith,  and  Charity 
valleys]  are  in  fact  the  lips  of  consecutive  lake  basins  scooped 
out  by  ice. 

.  .  .  Water  tends  to  form  deep  V-shaped  canons,  while  ice  pro- 
duces broad  valleys  with  lakes  and  meadows.  ...  I  know  not 
how  general  these  distinctions  may  be,  but  certainly  the  Coast 
range  of  this  State  is  characterized  by  rounded  summits  and 
ridges,  and  deep  V-shaped  canons,  while  the  high  Sierras  are 
characterized  on  the  contrary  by  sharp,  spire-like,  comb-like 
summits,  and  broad  valleys ;  and  this  difference  1  am  convinced 
is  due  in  part  at  least  to  the  action  of  water  on  the  one  hand, 
and  of  ice  on  the  other." 

King  (1878)^^  assigned  to  glacial  erosion  a  command- 
ing position  in  mountain  sculpture.  In  regard  to  the 
Uintas,  he  says : 

"Glacial  erosion  has  cut  almost  vertically  down  through  tho 
beds  carving  immense  amphitheatres  with  basin  bottoms  con- 
taining numerous  Alpine  lakes.  .  .  .  Post-glacial  erosion  has  done 


146  A  CENTURY  OF  SCIENCE 

an  absolutely  trivial  work.  There  is  not  a  particle  of  direct 
evidence,  so  far  as  I  can  see,  to  warrant  the  belief  that  these 
U-shaped  canons  were  given  their  peculiar  form  by  other  means 
than  the  actual  ploughing  erosion  of  glaciers.  .  .  /' 

These  contributions  from  the  Cordilleras  corroborat- 
ing the  conclusions  of  Ramsay  (1862),  Tyndall  (1862), 
Jukes  (1862),  Hector  (1863),  Logan  (1863),  Close  (1870), 
and  James  Geikie  (1875),  made  little  impression.  The 
views  of  Lyell  (1833),  Ball  (1863),  J.  W.  Dawson  (1864), 
Falconer  (1864),  Studer  (1864),  Murchison  (1864,  1870), 
Ruskin  (1865),  Rutimeyer  (1869),  Whymper  (1871), 
Bonney  (1873),  Pfaff  (1874),  Gurlt  (1874),  Judd  (1876), 
prevailed,  and  the  conclusions  of  Davis  in  1882^^  fairly 
expressed  the  prevailing  belief  in  Europe  and  in 
America : 

**The  amount  of  glacial  erosion  in  the  central  districts  has 
been  very  considerable,  but  not  greatly  in  excess  of  pre-glacial 
soils  and  old  talus  and  alluvial  deposits.  Most  of  the  solid  rock 
that  was  carried  away  came  from  ledges  rather  than  from  val- 
leys; and  glaciers  had  in  general  a  smoothing  rather  than  a 
roughening  effect.  In  the  outer  areas  on  which  the  ice  advanced 
it  only  rubbed  down  the  projecting  points;  here  it  acted  more 
frequently  as  a  depositing  than  as  an  eroding  agent. ' ' 

During  the  past  quarter-century  the  cleavage  in  the 
ranks  of  geologists,  brought  about  by  Ramsay's  classic 
paper,  has  remained.  Fairchild  and  others  in  America, 
Heim,  Bonney,  and  Garwood  in  Europe  argue  for  insig- 
nificant erosion  by  glaciers ;  and  Gannet,  Davis,  Gilbert, 
Tarr  in  America  followed  by  Austrian  workers  present 
evidence  for  erosion  on  a  gigantic  scale.  A  perusal  of 
the  voluminous  literature  in  the  Journal  and  elsewhere 
shows  that  the  difference  of  opinion  is  in  part  one  of 
terms,  the  amount  of  erosion  rather  than  the  fact  of 
erosion;  it  also  arises  from  failure  to  differentiate  the 
work  of  mountain  glaciers  and  continental  ice  sheets,  of 
Pleistocene  glaciers  and  their  present  diminished  repre- 
sentatives. The  irrelevant  contribution  of  physicists  has 
also  made  for  confusion. 

It  is  interesting  to  note  that  the  criteria  for  erosion 
of  valleys  by  glaciers  has  long  been  established  and 
by  workers  in  different  countries.     Ramsay   (1862)   in 


INTERPRETATION  OF  LAND  FORMS       147 

England  outlined  the  problem  and  presented  generalized 
evidence.  Hector  (1863)  in  New  Zealand  pointed  out 
the  significance  of  discordant  drainage,  the  **  hanging 
valleys''  of  Gilbert.  The  U-form,  the  broad  lake-dotted 
floor,  and  the  presence  of  cirques  and  the  process  of 
plucking  were  probably  first  described  by  LeConte 
(1873)  in  America.  The  truncation  of  valley  spurs  by 
glaciers  pointed  out  by  Studer  in  the  Kerguelen  Islands 
(1878)  was  used  by  Chamberlin  (1883)  as  evidence  of 
glacial  scouring. 

Conclusion, 

During  the  past  century  many  principles  of  land 
sculpture  have  emerged  from  the  fog  of  intellectual 
speculation  and  unorganized  observation  and  taken  their 
place  among  generally  accepted  truths.  Many  of  them 
are  no  longer  subjects  of  controversy.  Erosion  has 
found  its  place  as  a  major  geologic  agent  and  has  given 
a  new  conception  of  natural  scenery.  Lofty  mountains 
are  no  longer  ** ancient  as  the  sun,"  they  are  youthful 
features  in  process  of  dissection;  valleys  and  canyons 
are  the  work  of  streams  and  glaciers ;  fiords  are  erosion 
forms;  waterfalls  and  lakes  are  features  in  process  of 
elimination;  many  plains  and  plateaus  owe  their  form 
and  position  to  long-continued  denudation.  Modern 
landscapes  are  no  longer  viewed  as  original  features  or 
the  product  of  a  single  agent  acting  at  a  particular  time, 
but  as  ephemeral  forms  which  owe  their  present  appear- 
ance to  their  age  and  the  particular  forces  at  work  upon 
them  as  well  as  to  their  original  structure. 

It  is  interesting  to  note  the  halting  steps  leading  to  the 
present  viewpoint,  to  find  that  decades  elapsed  between 
the  formulation  of  a  theory  or  the  recording  of  signifi- 
cant facts  and  their  final  acceptance  or  rejection,  and  to 
realize  that  the  organization  of  principles  and  observa- 
tions into  a  science  of  physiography  has  been  the  work 
of  the  present  generation.  Progress  has  been  condi- 
tioned by  a  number  of  factors  besides  the  intellectual 
ability  of  individual  workers. 

The  influence  of  locality  is  plainly  seen.  Convincing 
evidence  of  river  erosion  was  obtained  in  central  France, 
the  Pacific  Islands,  and  the  Colorado  Plateau — regions 


148  A  CENTURY  OF  SCIENCE 

in  which  other  causes  were  easily  eliminated.  Sculpture 
by  glaciers  passed  beyond  the  theoretical  stage  when  the 
simple  forms  of  the  Sierras  and  New  Zealand  Alps  were 
described.  The  origin  of  loess  was  first  discerned  in  a 
region  where  glacial  phenomena  did  not  obscure  the 
vision.  The  complexity  of  the  Glacial  period  asserted  by 
geologists  of  the  Middle  West  was  denied  by  eastern 
students.  The  work  of  waves  on  the  English  coast 
impressed  British  geologists  to  such  an  extent  that  plains 
of  denudation  and  inland  valleys  were  ascribed  to 
ocean  work. 

In  the  establishment  of  principles,  the  friendly  inter- 
change of  ideas  has  yielded  large  returns.  Many  of  the 
fundamental  conceptions  of  earth  sculpture  have  come 
from  groups  of  men  so  situated  as  to  facilitate  criticism. 
It  is  impossible,  even  if  desirable,  to  award  individual 
credit  to  Venetz,  Charpentier,  and  Agassiz  in  the  formu- 
lation of  the  glacial  theory ;  and  the  close  association  of 
Agassiz  and  Dana  in  New  England  and  of  Chamberlin 
and  Irving  in  Wisconsin  was  undoubtedly  helpful  in 
establishing  the  theory  of  continental  glaciation.  From 
the  intimate  companionship  in  field  and  laboratory  of 
Button,  Playfair  and  Hope,  arose  the  profound  influence 
of  the  Edinburgh  school,  and  the  sympathetic  cooperation 
of  Powell,  Gilbert,  and  Button  has  given  to  the  world  its 
classics  in  the  genetic  study  of  land  forms. 

The  influence  of  ideas  has  been  closely  associated  with 
clarity,  conciseness,  and  attractiveness  of  presentation. 
Button  is  known  through  Playfair,  Agassiz 's  contribu- 
tions to  glacial  geology  are  known  to  every  student,  while 
Venetz,  Charpentier,  and  Hugi  are  only  names.  Cuvier's 
discourses  on  dynamical  geology  were  reprinted  and 
translated  into  English  and  German,  but  Lamarck's 
*^Hydrogeologie"  is  known  only  to  book  collectors.  The 
verbose  works  of  Guettard,  although  carrying  the  same 
message  as  Playfair 's  ** Illustrations'*  and  Desmarest's 
'* Memoirs,"  are  practically  unknown,  as  is  also  Horace 
B.  Hayden's  treatise  (1821)  on  the  drift  of  eastern 
North  America.  It  has  been  well  said  that  the  world- 
wide influence  of  American  physiographic  teaching  is  due 
in  no  small  part  to  the  masterly  presentations  of  Gilbert 
and  Davis. 


INTERPEETATION  OF  LAND  FORMS       149 

It  is  surprising  to  note  the  delays,  the  backward  steps, 
and  the  duplication  of  effort  resulting  from  lack  of 
familiarity  with  the  work  of  the  pioneers.  Sabine  says 
in  1864:^3 

"It  often  happens,  not  unnaturally,  that  those  who  are  most 
occupied  with  the  questions  of  the  day  in  an  advancing  science 
retain  but  an  imperfect  recollection  of  the  obligations  due 
to  those  who  laid  the  first  foundations  of  our  subsequent 
knowledge. ' ' 

The  product  of  intellectual  effort  appears  to  be  con- 
ditioned by  time  of  planting  and  character  of  soil  as  well 
as  by  quantity  of  seed.  For  example:  Erosion  by 
rivers  was  as  clearly  shown  by  Desmarest  as  by  Dana  and 
Newberry  50  years  later.  Criteria  for  the  recognition  of 
ancient  fluviatile  deposits  were  established  by  James 
Deane  in  1847  in  a  study  of  the  Connecticut  Valley 
Triassic.  Agassiz's  proof  that  ice  is  an  essential  factor 
in  the  formation  of  till  is  substantially  a  duplication  of 
Dobson's  observations  (1826). 

The  volumes  of  the  Journal  with  their  very  large  num- 
ber of  articles  and  reviews  dealing  with  geology  show 
that  the  interpretation  of  land  forms  as  products  of 
subaerial  erosion  began  in  France  and  French  Switzer- 
land during  the  later  part  of  the  eighteenth  century  as  a 
phase  of  the  intellectual  emancipation  following  the  Rev- 
olution. Scotland  and  England  assumed  the  leadership 
for  the  first  half  of  the  nineteenth  century,  and  the  first 
100  volumes  of  the  Journal  show  the  profound  influence 
of  English  and  French  teaching.  In  America,  independ- 
ent thinking,  early  exercised  by  the  few,  became  general 
with  the  establishment  of  the  Federal  survey,  the  increase 
in  university  departments,  geological  societies  and  peri- 
odicals, and  has  given  to  Americans  the  responsibilities 
of  teachers. 

Bibliography, 

(In  the  following  list  *Hhis  Journal"  refers  to  the  American  Journal 
of  Science.) 

^  Wilson,  J.  W.,  Bursting  of  lakes  through  mountains,  this  Journal,  3, 
253,  1821. 

^  Whitney,  J.  D.,  Progress  of  the  Geological  Survey  of  California,  this 
Journal,  38.  263-264,  1864. 

« Playfair,  John,  Illustrations  of  the  Huttonian  theory  of  the  earth,  Edin- 
burgh, 1802. 


150  A  CENTURY  OF  SCIENCE 

•  Kain,  J.  H.,  Remarks  on  the  mineralogy  and  geology  of  northwestern 
Virginia  and  eastern  Tennessee,  this  Journal,  1,  60-67,  1819. 

'Hitchcock,  Edward,  Geology,  etc.,  of  regions  contiguous  to  the  Connect- 
icut, this  Journal,  7,  1-30,  1824. 

•  Buckland,  Wm.,  Reliquiae  diluviansB,  this  Journal,  8,  150,  317,  1824. 
'  Phillips,  John,  Geology  of  Yorkshire,  this  Journal,  21,  17-20,  1832. 
*Scrope,  G.  P.,  Excavation  of  valleys,  Geol.  Soc,  London,  No.  14,  1830. 

•  Hayes,  G.  E.,  Remarks  on  geology  and  topography  of  western  New 
York,  this  Journal,  35,  88-91,  1839. 

^°  Seventh  Meeting  of  the  British  Association  for  the  Advancement  of 
Science,  this  Journal,  33,  288,  1838. 

"  Darwin,  Charles,  Geological  observations  on  the  volcanic  islands  and 
parts  of  South  America,  etc.,  second  part  of  the  Voyage  of  the  ''Beagle," 
during  1832-1836.     London,  1844. 

^  Hildreth,  S,  P.,  Observations,  etc.,  valley  of  the  Ohio,  this  Journal,  29, 
1-148,  1836. 

"  Geddes,  James,  Observations  on  the  geological  features  of  the  south 
side  of  Ontario  vaUey,  this  Journal,  11,  213-218,  1826. 

"  Conrad,  T.  A.,  Notes  on  American  geology,  this  Journal,  35,  237-251, 
1839. 

"  Warren,  G.  K.,  Preliminary  report  of  explorations  in  Nebraska  and 
Dakota,  this  Journal,  27,  380,  1859. 

"  Lesley,  J.  P.,  Observations  on  the  Appalachian  region  of  southern 
Virginia,  this  Journal,  34,  review,  413-415,  1862. 

*'  Hitchcock,  Edward,  First  anniversary  address  before  the  Association 
of  American  Geologists,  this  Journal,  41,  232-275,  1841. 

**Dana,  J.  D.,  On  denudation  in  the  Pacific,  this  Journal,  9,  48-62,  1850. 

,  On  the  degradation  of  the  rocks  of  New  South  Wales  and 

formation  of  valleys,  this  Journal,  9,  289-294,  1850. 

"•  Hubbard,  O.  P.,  On  the  condition  of  trap  dikes  in  New  Hampshire  an 
evidence  and  measure  of  erosion,  this  Journal,  9,  158-171,  1850. 

^  Hayden,  F,  V.,  Some  remarks  in  regard  to  the  period  of  elevation  of 
the  Rocky  Mountains,  this  Journal,  33,  305-313,  1862. 

*^  Newberry,  J.  S.,  Colorado  River  of  the  West,  this  Journal,  33,  review, 
387-403,  1862. 

^  Jukes,  J.  B.,  Address  to  the  Geological  Section  of  the  British  Associa- 
tion at  Cambridge,  Quart.  Jour.  Geol.  Soc,  18,  1862,  this  Journal,  34,  439, 
1862. 

^Powell,  J.  W.,  Exploration  of  the  Colorado  River  of  the  West,  1875. 
For  Powell's  preliminary  article  see  this  Journal,  5,  456-465,  1873. 

**McGee,  W.  J.,  Three  formations  of  the  Middle  Atlantic  slope,  this 
Journal,  35,  120,  328,  367,  448,  1888. 

"Davis,  W.  M.,  Topographic  development  of  the  Triassic  formation  of 
the  Connecticut  Valley,  this  Journal,  37,  423-434,  1889. 

^  Percival,  J.  G.,  Geology  of  Connecticut,  1842. 

"Kerr,  W.  C,  Origin  of  some  new  points  in  the  topography  of  North 
Carolina,  this  Journal.  21,  216-219,  1881. 

^McGee,  W.  J.,  The  classification  of  geographic  forms  by  genesis,  Nat. 
Geogr.  Mag.,  1,  27-36,  1888. 

"Davis,  W.  M.,  The  rivers  and  valleys  of  Pennsylvania,  Nat.  Geogr. 
Mag.,  1,  183-253,  1889. 

,  The  rivers  of  northern  New  Jersey  with  notes  on  the  classi' 

fication  of  rivers  in  general,  ibid.,  2,  81-110,  1890. 

""Silliman,  Benjamin,  Notice  of  Horace  H.  Hayden 's  geological  essays, 
this  Journal,  3,  49,  1821. 

^^  Cornelius,  Elias,  Account  of  a  singular  position  of  a  granite  rock,  this 
Journal,  2,  200-201,  1820. 


INTERPRETATION  OF  LAND  FORMS       151 

"  Finch,  John,  On  the  Celtic  antiquities  of  America,  this  Journal,  7,  149- 
161,  1824. 

"  Finch,  John,  Geological  essay  on  the  Tertiary  formations  in  America, 
this  Journal,  7,  31-43,  1824. 

"Conybeare  and  Phillips,  Outlines  of  the  geology  of  England  and  Wales, 
this  Journal,  7,  210,  211,  1824. 

"Hayden,  Horace  H.,  Geological  essays,  1-412,  1821,  this  Journal,  3, 
47-57,  1821. 

"Jackson,  C.  T.,  Reports  on  the  geology  of  the  State  of  Maine,  and  on 
the  public  lands  belonging  to  Maine  and  Massachusetts,  this  Journal,  36, 
153,  1839. 

"  Gibson,  J.  B.,  Remarks  on  the  geology  of  the  lakes  and  the  valley  of 
the  Mississippi,  this  Journal,  29,  201-213,  1836. 

"  Phillips,  John,  Geology  of  Yorkshire,  this  Journal,  21,  14-15,  1832. 

"Granger,  Ebenezer,  Notice  of  a  curious  fluted  rock  at  Sandusky  Bay, 
Ohio,  this  Journal,  6,  180,  1823. 

^'Dobson,  Peter,  Remarks  on  bowlders,  this  Journal,  10,  217-218,  1826. 

"  Murchison,  R.  I,,  Address  at  anniversary  meeting  of  the  Geological 
Society  of  London,  this  Journal,  43,  200-201,  1842. 

*^  Buckland,  W.,  On  the  evidence  of  glaciers  in  Scotland  and  the  north 
of  England,  Proc.  London  Geol.  Soc,  3,  1841. 

**  Third  annual  meeting  of  the  Association  of  American  Geologists  and 
Naturalists,  this  Journal,  43,  154,  1842;  Abstract  of  proceedings  of  the 
fourth  session  of  the  Association  of  American  Geologists  and  Naturalists, 
ibid.,  45,  321,  1843. 

**  Rogers,  H.  D.,  Address  delivered  before  Association  of  American  Geol- 
ogists and  Naturalists,  this  Journal,  47,  275,  1844. 

*^Agassiz,  Louis,  The  erratic  phenomena  about  Lake  Superior,  this 
Journal,  10,  83-101,  1850. 

*"Desor,  E.,  On  the  drift  of  Lake  Superior,  this  Journal,  13,  93-109, 
1852;    Post-Pliocene  of  the  southern  States,  etc.,  14,  49-59,  1852. 

"  Dana,  J.  D.,  Manual  of  geology,  546,  Philadelphia,  1863. 

**  Dana,  J.  D.,  on  the  Quaternary,  or  post-Tertiary  of  the  New  Haven 
region,  this  Journal,  1,  1-5,  1871. 

^  Matthew,  G.  F,,  Surface  geology  of  New  Brunswick,  this  Journal,  2, 
371-372,  1871. 

"  Maclaren,  Charles,  The  glacial  theory  of  Prof.  Agassiz,  this  Journal, 
42,  365,  1842. 

''^  Daly,  R.  A.,  Problems  of  the  Pacific  Islands,  this  Journal,  41,  153-186, 
1916. 

'^  Catlin,  George,  Account  of  a  journey  to  the  Coteau  des  Prairies,  this 
Journal,  38,  138-146,  1840. 

•^  Hilgard,  E.  W.,  Remarks  on  the  drift  of  the  western  and  southern  States 
and  its  relation  to  the  glacier  and  ice-berg  theories,  this  Journal,  42,  343- 
347,  1866. 

**  Hall,  C.  E.,  Glacial  phenomena  along  the  Kittatinny  or  Blue  Mountain, 
Pennsylvania,  this  Journal,  11,  review,  233,  1876. 

"  Stevens,  R.  P.,  On  glaciers  of  the  glacial  era  in  Virginia,  this  Journal, 
6,  371-373,  1873. 

^  Rogers,  W.  B.,  On  the  gravel  and  cobble-stone  deposits  of  Virginia  and 
the  Middle  States,  Proc.  Boston  Soc.  Nat.  Hist.,  18,  1875;  this  Journal, 
11,  60-61,  1876. 

"  Kerr,  W.  C,  Origin  of  some  new  points  in  the  topography  of  North 
Carolina,  this  Journal,  21,  216-219,  1881. 

■*  Gilbert,  G.  K.,  On  certain  glacial  and  post-glacial  phenomena  of  the 
Maumee  valley,  this  Journal,  1,  339-345,  1871. 

^  Chamberlin,  T.  C,  On  the  geology  of  eastern  Wisconsin,  Geol.  of 
"Wisconsin,  2,  1877  j    this  Journal,  15,  61,  406,  1878. 


152  A  CENTURY  OF  SCIENCE 

^  Chamberlin,  T.  C,  Preliminary  paper  on  the  terminal  moraine  of  the 
second  glacial  epoch,  U.  S.  Geol.  Survey,  Third  Ann.  Kept.,  291-402,  1883. 

«^  Wright,  G.  F.,  Unity  of  the  glacial  epoch,  this  Journal,  44,  351-373, 
1892. 

Upham,  Warren,  The  diversity  of  the  glacial  drift  along  its  boundary, 
ibid.,  47,  358-365,  1894. 

Wright,  G.  F.,  Theory  of  an  interglacial  submergence  in  England,  ibid., 
43,  1-8,  1892. 

Chamberlin,  T.  C,  Diversity  of  the  glacial  period,  ibid.,  45,  171-200, 
1893. 

Dana,  J.  D.,  On  New  England  and  the  upper  Mississippi  basin  in  the 
glacial  period,  ibid.,  46,  327-330,  1893. 

Wright,  G.  F.,  Continuity  of  the  glacial  period,  ibid.,  47,  161-187,  1894. 

Chamberlin,  T.  C.  and  Leverett,  F.,  Further  studies  of  the  drainage 
features  of  the  upper  Ohio  basin,  ibid.,  47,  247-282,  1894. 

^  Pumpelly,  Raphael,  Geological  researches  in  China,  Japan,  and  Mon^ 
golia,  Smithsonian  Contributions,  No.  202,  1866. 

**  Kingsmill,  T.  W.,  The  probable  origin  of  ''loess"  in  North  China 
and  eastern  Asia,  Quart.  Jour.  Geol.  Soc,  27,  No.  108,  1871. 

^  Pumpelly,  Raphael,  The  relation  of  secular  rock-disintegration  to  loess, 
glacial  drift  and  rock  basins,  this  Journal,  17,  135,  1879. 

^  Binney,  A.,  Some  geologic  features  at  Natchez  on  the  Mississippi  River, 
Proc.  Boston  Soc.  Nat.  Hist.,  2,  126-130,  1848. 

®®  Hilgard,  E.  W.,  The  loess  of  Mississippi  Valley,  and  the  eolian  hypoth- 
esis, this  Journal,  18,  106-112,  1879. 

*^  Chamberlin,  T.  C.,  Supplementary  hypothesis  respecting  the  origin  of 
the  loess  of  the  Mississippi  Valley,  Jour.  Geol.,  5,  795-802,  1897. 

^  Ramsay,  A.  C,  On  the  glacial  origin  of  certain  lakes  in  Switzerland, 
the  Black  Forest,  Great  Britain,  Sweden,  North  America,  and  elsewhere, 
Quart.  Jour.  Geol.  Soc,  1862;  this  Journal,  35,  324-345,  1863.  Preliminary 
statements  of  this  theory  appeared  in  1859  and  1860. 

^  Whittlesey,  Charles,  Smithsonian  Contributions,  No.  197,  1864. 

™  LeConte,  Joseph,  On  some  of  the  ancient  glaciers  of  the  Sierras,  this 
Journal,  5,  325-342,  1873,  10,  126-139,  1875. 

"  King,  aarence,  U.  S.  Geol.  Expl.  40th  Par.,  1,  459-529,  1878. 

"Davis,  W.  M.,  Glacial  erosion,  Proc.  Boston  Soc.  Nat.  Hist.,  22,  58, 
1882. 

'^  Sabine,  Sir  Edward,  Address  of  the  president  of  the  Royal  Society, 
this  Journal,  37,  108,  1864. 


IV 

A  CENTURY  OF  GEOLOGY THE  GROWTH  OF 

KNOWLEDGE  OF  EARTH  STRUCTURE 

By  JOSEPH  BARREL.L 

Introduction 
The  Intellectual  Viewpoint  in  1818, 

IN  1818,  the  year  of  the  founding  of  the  Journal,  the 
natural  sciences  were  still  in  their  infancy  in  Europe. 
Geology  was  still  subordinate  to  mineralogy,  was 
hardly  recognized  as  a  distinct  science,  and  consisted  in 
little  more  than  a  description  of  the  character  and  distri- 
bution of  minerals  and  rocks.  America  was  remote  from 
the  Old  World  centers  of  learning.  The  energy  of  the 
young  nation  was  absorbed  in  its  own  expansion,  and  but 
a  few  of  those  who  by  aptitude  were  fitted  to  increase 
scientific  knowledge  were  even  conscious  of  the  existence 
of  such  a  field  of  endeavor.  Under  these  circumstances 
the^  educative  field  open  to  a  journal  of  science  in  the 
United  States  was  an  almost  virgin  soil.  Original  con- 
tributions could  most  readily  be  based  upon  the  natural 
history  of  the  New  World,  and  the  founder  of  the  Journal 
showed  insight  appreciative  of  the  situation  in  stating  in 
the  ''Plan  of  the  Work*'  in  the  introduction  to  the  first 
volume  that  ''It  will  be  a  leading  object  to  illustrate 
American  Natural  History,  and  especially  our  Mrs- 
ERALOGY  and  Geology. 

At  this  time  educated  people  were  still  satisfied  that 
the  whole  knowledge  of  the  origin  and  development  of 
the  earth  so  far  as  man  could  or  should  know  it  was 
embraced  in  the  Book  of  Genesis.  They  were  inclined  to 
look  with  misgiving  at  attempts  to  directly  interrogate  the 
earth  as  to  its  history.     Philosophers  such  as  Descartes 


154  A  CENTURY  OF  SCIENCE 

and  Liebnitz,  the  cosmogonists  de  Maillet  and  Buffon 
had  been  less  instrumental  in  developing  science  than  in 
fitting  a  few  facts  and  many  speculations  to  their  systems 
of  philosophy.  By  the  opening  of  the  nineteenth  cen- 
tury, however,  men  of  learning  were  coming  to  appre- 
ciate that  the  way  to  advance  science  was  to  experiment 
and  observe,  to  collect  facts  and  discourage  unfounded 
speculation.  Silliman's  insight  into  the  needs  of  geologic 
science  is  shown  in  the  following  quotation  (1,  pp.  6, 
7, 1818) : 

' '  Our  geology,  also,  presents  a  most  interesting  field  of  inquiry. 
A  grand  outline  has  recently  been  drawn  by  Mr.  Maclure,  with 
a  masterly  hand,  and  with  a  vast  extent  of  personal  observation 
and  labour :  but  to  fill  up  the  detail,  both  observation  and  labour 
still  more  extensive  are  demanded;  nor  can  the  object  be 
effected,  till  more  good  geologists  are  formed,  and  distributed 
over  our  extensive  territory. 

To  account  for  the  formation  and  changes  of  our  globe,  by 
excursions  of  the  imagiuation,  often  splendid  and  imposing,  but 
usually  visionary,  and  almost  always  baseless,  was,  till  within 
half  a  century,  the  business  of  geological  speculations ;  but  this 
research  has  now  assumed  a  more  sober  character;  the  science 
of  geology  has  been  reared  upon  numerous  and  accurate  obser- 
vations of  facts;  and  standing  thus  upon  the  basis  of  induc- 
tion, it  is  entitled  to  a  rank  among  those  sciences  which  Lord 
Bacon's  Philosophy  has  contributed  to  create.  Geological 
researches  are  now  prosecuted  by  actually  exploring  the  struc- 
ture and  arrangement  of  districts,  countries,  and  continents. 
The  obliquity  of  the  strata  of  most  rocks,  causing  their  edges 
to  project  in  many  places  above  the  surface ;  their  exposure,  in 
other  instances  on  the  sides  or  tops  of  hills  and  mountains; 
or,  in  consequence  of  the  intersection  of  their  strata,  by  roads, 
canals,  and  river-courses,  or  by  the  wearing  of  the  ocean;  or 
their  direct  perforation,  by  the  shafts  of  mines ;  all  these  causes, 
and  others,  afford  extensive  means  of  reading  the  interior 
structure  of  the  globe. 

The  outlines  of  American  geology  appear  to  be  particularly 
grand,  simple,  and  instructive ;  and  a  knowledge  of  the  import- 
ant facts,  and  general  principles  of  this  science,  is  of  vast  prac- 
tical use,  as  regards  the  interests  of  agriculture,  and  the  research 
for  useful  minerals.  Geological  and  mineralogical  descriptions, 
and  maps  of  particular  states  and  districts,  are  very  much 
needed  in  the  United  States;  and  to  excite  a  spirit  to  furnish 
them  will  form  one  leading  object  of  this  Journal. '* 


KNOWLEDGE  OF  EARTH  STRUCTURE     155 

The  Prolonged  Influence  of  Outgrown  Ideas, 

Those  interested  in  any  branch  of  science  should,  as  a 
matter  of  education,  read  the  history  of  that  special  sub- 
ject. A  knowledge  of  the  stages  by  which  the  present 
development  has  been  attained  is  essential  to  give  a 
proper  perspective  to  the  literature  of  each  period. 
Much  of  the  existing  terminology  is  an  inheritance  from 
the  first  attempts  at  nomenclature,  or  may  rest  upon 
theories  long  discarded.  Popular  notions  at  variance 
with  advanced  teaching  are  often  the  forgotten  inherit- 
ance of  a  past  generation. 

Gneiss,  trap,  and  Old  Red  Sandstone  are  names  which 
we  owe  to  Werner.  The  *^ Tertiary  period''  and  **driff 
are  relics  of  an  early  terminology.  The  geology  of 
tourist  circulars  still  speaks  of  canyons  as  made  by  **  con- 
vulsions of  nature.''  Popular  writers  still  attribute  to 
geologists  a  belief  in  a  molten  earth  covered  by  a  thin 
crust.  Within  the  present  century  the  eighteenth  cen- 
tury speculations  of  Werner  and  his  predecessors,  postu- 
lating a  supposed  capacity  of  water  to  seep  through  the 
crust  into  the  interior  of  the  earth,  resulting  in  a  hypo- 
thetical progressive  desiccation  of  the  surface,  views  long 
abandoned  by  most  modern  geologists,  have  been  revived 
by  an  astronomer  into  a  theory  of  *  *  planetology. " 

A  review  of  the  literature  of  a  century  brings  to  light 
certain  tendencies  in  the  growth  of  science.  Each  decade 
has  witnessed  a  larger  accumulation  of  observed  facts 
and  a  fuller  classification  of  these  fundamental  data,  but 
the  pendulum  of  interpretative  theory  swings  away  from 
the  path  of  progress,  now  to  one  side,  now  to  the  other, 
testing  out  the  proper  direction.  For  decades  the  under- 
standing of  certain  classes  of  facts  may  be  actually  retro- 
gressive. A  retrospect  shows  that  certain  minds,  keen 
and  unfettered  by  a  prevailing  theory,  have  in  some 
directions  been  in  advance  of  their  generation.  But  the 
judgment  of  the  times  had  not  sufficient  basis  in  knowl- 
edge for  the  separation  and  acceptance  of  their  truer 
views  from  the  contemporaneous  tangle  of  false  inter- 
pretations. 

An  interesting  illustration  of  these  statements  regard- 


156  A  CENTURY  OF  SCIENCE 

ing  the  slow  settling  of  opinion  may  be  cited  in  regard  to 
the  significance  of  the  dip  of  the  Triassic  formations  of 
the  eastern  United  States.  The  strata  of  the  Massachu- 
setts-Connecticut basin  possess  a  monoclinal  easterly  dip 
which  averages  about  20  degrees  to  the  east.  Those  of 
the  New  Jersey-Pennsylvania- Virginia  basin  possess  a 
similar  dip  to  the  northwest.  Both  basins  are  cut  by 
great  faults  and  the  dip  is  now  accepted  by  practically 
all  geologists  as  due  to  rotation  of  the  crust  blocks 
away  from  a  geanticlinal  axis  between  the  two  basins. 
Edward  Hitchcock,  whose  work  from  the  first  shows  an 
interpretative  quality  in  advance  of  his  time,  states  in 
1823  (6,  74)  regarding  the  dip  of  the  Connecticut  valley 
rocks : 

"There  is  reason  to  believe  that  Mount  Toby,  the  strata  of 
which  are  almost  horizontal,  exhibits  the  original  dip  of  these 
rocks,  and  that  those  cases  in  which  they  are  more  highly  inclined 
are  the  result  of  some  Plutonian  convulsion.  Such  irregularity 
in  the  dip  of  coal  fields  is  no  uncommon  occurrence." 

In  Hitchcock's  Geology  of  Massachusetts,  published  in 
1833,  ten  years  later,  geological  structure  sections  of  the 
Connecticut  Valley  rocks  are  given,  the  facts  are  dis- 
cussed in  detail  and  the  dip  ascribed  to  the  elevatory 
forces.     He  says  (1.  c,  pp.  213,  223) : 

"If  it  were  possible  to  doubt  that  the  new  red  sandstone 
formation  was  deposited  from  water,  the  surface  of  some  of  the 
layers  of  this  shale  would  settle  the  question  demonstrably. 
For  it  exhibits  precisely  those  gentle  undulations,  which  the 
loamy  bottom  of  every  river  with  a  moderate  current,  presents. 
(No.  198.)  But  such  a  surface  could  never  have  been  formed 
while  the  layers  had  that  high  inclination  to  the  horizon,  which 
many  of  them  now  present :  so  that  we  have  here,  also,  decisive 
evidence  that  they  have  been  elevated  subsequently  to  their 
deposition.    .    .    . 

The  objection  of  a  writer  in  the  American  Journal  of  Science, 
that  such  a  height  of  waters  as  would  deposit  Mount  Toby,  must 
have  produced  a  lake  nearly  to  the  upper  part  of  New  Hamp- 
shire, in  the  Connecticut  Valley,  and  thus  have  caused  the  same 
sandstone  to  be  produced  higher  up  that  valley  than  Northfield, 
loses  its  force,  when  it  is  recollected  that  this  formation  was 
deposited  before  its  strata  were  elevated.  For  the  elevating 
force  undoubtedly  changed  the  relative  level  of  different  parts 


Courtesy  of  Popular  Science  Monthly. 


C  ^^^^^^^-^-^-^^^^^  ^:^^^c^^^^^C^6^t>-^ 


KNOWLEDGE  OF  EARTH  STRUCTURE     157 

of  the  country.  In  this  case,  the  disturbing  force  must  have 
acted  beneath  the  primary  rocks.  And  besides,  we  have  good 
evidence  which  will  be  shown  by  and  by,  that  our  new  red 
sandstone  was  formed  beneath  the  ocean.  We  cannot  then 
reason  on  this  subject  from  present  levels." 

In  1840,  H.  D.  Rogers,  a  geologist  who  has  acquired  a 
more  widely  known  name  than  Hitchcock,  but  who  in 
reality  showed  an  inferior  ability  in  interpretation,  made 
the  following  statements  in  explanation  of  the  regional 
monoclinal  dip  of  the  New  Jersey  Triassic  rocks  averag- 
ing 15  to  20  degrees  to  the  northwest  :^ 

' '  Their  materials  give  evidence  of  having  been  swept  into  this 
estuary,  or  great  ancient  river,  from  the  south  and  southeast, 
by  a  current  producing  an  almost  universal  dip  of  the  beds 
towards  the  northwest,  a  feature  clearly  not  caused  by  any 
uplifting  agency,  but  assumed  originally  at  the  time  of  their 
deposition,  in  consequence  of  the  setting  of  the  current  from  the 
opposite  or  southeastern  shore.'' 

In  1842,  at  the  third  annual  meeting  of  the  Association 
of  American  Geologists  both  H.  D.  and  W.  B.  Rogers 
argued  (43,  170,  1842)  against  Sir  Charles  Lyell  and  E. 
Hitchcock  that  the  present  dip  of  the  Triassic  was  the 
original  slope  of  deposition,  stating  among  other  reasons 
that  the  footprints  impressed  upon  the  sediments  often 
showed  a  slipping  and  a  pushing  of  the  soft  clay  in  the 
direction  of  the  downhill  slope.  In  1858  H.  D.  Rogers 
still  held  to  the  same  views  of  original  dip,^  notwithstand- 
ing that  a  moderate  amount  of  observation  on  the  mud- 
cracked  and  rain-pitted  layers  would  have  supplied  the 
proof  that  such  must  have  dried  as  horizontal  surfaces. 
The  idea  of  inclined  deposition  is  not  yet  wholly  dead  as 
it  has  been  suggested  more  than  once  within  the  present 
generation  as  a  means  of  escaping  from  the  necessity  of 
accepting  the  very  great  thicknesses  of  this  and  similar 
formations.  Thus,  as  Brogger  has  remarked  in  another 
connection, — the  ghosts  of  the  old  time  stand  ever  ready 
to  reappear. 

In  the  present  essay  on  the  rise  of  structural  geology 
as  reflected  through  a  century  of  publication  in  the 
Journal,  attention  will  be  given  especially  to  two  fields, 
that  of  structures  connected  with  igneous  rocks  and  that 

10 


158  A  CENTURY  OF  SCIENCE 

of  structures  connected  with  mountain  making,  and 
emphasis  will  be  placed  upon  the  growth  of  understand- 
ing rather  than  upon  the  accumulating  knowledge  of 
details.  The  growth  in  both  of  these  divisions  of  struc- 
tural geology  is  well  illustrated  in  the  volumes  of  the 
Journal. 

structures  and  Relationships  of  Igneous  Rocks, 
Opposed  Interpretations  of  Plutonists  and  Neptunists, 

During  the  first  quarter  of  the  nineteenth  century  the 
geologic  controversy  between  the  Plutonists  and  Nep- 
tunists was  at  its  height;  the  Plutonists,  following  the 
Scotchman,  Hutton,  holding  to  the  igneous  origin  of 
basalt  and  granite,  the  Neptunists,  after  their  German 
master,  Werner  of  Freiberg,  maintaining  that  these 
rocks  had  been  precipitated  from  a  primitive  universal 
ocean.  The  Plutonists,  although  time  has  shown  them  to 
have  been  correct  in  all  essential  particulars,  were  for  a 
generation  submerged  under  the  propaganda  carried  for- 
ward by  the  disciples  of  Werner.  The  **  Illustrations  of 
the  Huttonian  Theory  of  the  Earth,''  a  remarkable  clas- 
sic, worthy  of  being  studied  to-day  as  well  as  a  century 
ago,  was  published  in  1802  by  John  Playfair,  professor  of 
mathematics  in  the  University  of  Edinburgh  and  a  friend 
of  Hutton,  who  had  died  five  years  previously.  This 
volume  was  opposed  by  Robert  Jameson,  professor  of  nat- 
ural philosophy  in  the  same  university,  who  had  absorbed 
the  ideas  of  the  German  school  while  at  Freiberg 
and  published  in  1808  a  volume  on  the  **  Elements  of 
Geognosy,''  in  which  the  philosophy  of  Werner  is  fol- 
lowed throughout  and  even  obsidian  and  pumice  are 
argued  to  be  aqueous  precipitates.  The  authority  of  the 
Wernerian  autocracy  caused  its  nomenclature  to  be 
adopted  in  the  new  world,  but  strong  evidence  against 
its  interpretations  was  to  be  found  in  the  actual  struc- 
tural relations  displayed  by  the  igneous  rocks. 

Contributions  on  Volcanic  and  Intrusive  Rocks, 

The  accumulation  and  study  of  facts  constituted  the 
best  cure  for  an  erroneous  theory.  The  publications  of 
the  Journal  contributed  toward  this  end  by  articles  along 


KNOWLEDGE  OF  EARTH  STRUCTURE     159 

several  lines.  The  most  original  contributions  were  those 
which  dealt  with  the  areal  and  structural  geology  of 
eastern  North  America,  but  equally  valuable  at  that 
time  for  the  broadening  of  scientific  interest  were 
the  studies  on  the  volcanic  activities  of  the  Hawaiian 
Islands,  published  through  many  years.  Perhaps  most 
valuable  from  the  educative  standpoint  were  the  exten- 
sive republications  in  the  Journal  of  the  more  important 
European  researches,  making  them  accessible  to  Ameri- 
can readers.  In  volume  13  (1828),  for  example,  a  digest 
of  Scrope's  work  on  volcanoes  is  given,  covering  forty 
pages ;  and  of  Daubeny  on  active  and  extinct  volcanoes, 
running  over  seventy-five  pages  and  extending  into  vol. 
14.  Through  these  comprehensive  studies  the  nature  of 
volcanic  action  became  generally  understood  during  the 
first  half  of  the  nineteenth  century  and  the  original  pub- 
lications in  the  Journal  were  valuable  in  giving  a  knowl- 
edge of  the  activities  of  the  Hawaiian  volcanoes. 

Early  in  the  nineteenth  century  the  whole  of  America 
still  remained  to  be  explored  by  the  geologist.  The 
regions  adjacent  to  the  centers  of  learning  were  among 
the  first  to  receive  attention  and  the  Triassic  basin  of 
Connecticut  and  Massachusetts  yielded  information  in 
regard  to  the  nature  of  igneous  intrusion.  This  basin, 
of  unmetamorphic  shales  and  sandstones,  is  occupied  by 
the  Connecticut  River  except  at  its  southern  end.  The 
Formation  contains  within  it  sills,  dikes,  and  outflows  of 
basaltic  rocks  which  because  of  their  superior  resistance 
to  erosion  constitute  prominent  hills,  in  places  bounded 
by  cliffs. 

Silliman  in  1806^  described  East  Rock,  New  Haven, 
Connecticut,  as  a  whinstone,  trap,  or  basalt,  and 
accounted  for  its  presence  on  the  supposition  that  it  had 

**  actually  been  melted  in  the  bowels  of  the  earth  and  ejected 
among  the  superior  strata  by  the  force  of  subterraneous  fire, 
but  never  erupted  like  lava,  cooling  under  the  pressure  of  the 
superincumbent  strata  and  therefore  compact  or  nonvesicular, 
its  present  form  being  due  to  erosion." 

In  these  conclusions  Silliman  was  correct.  With  but  a 
limited  amount  of  experience  he  was  able  to  discriminate 
between  the  intrusive  and  effusive  rocks  and  saw  that  the 


160  A  CENTURY  OF  SCIENCE 

prominence  of  this  hill  was  due  to  the  erosion  of  the  sedi- 
ments which  once  surrounded  it. 

An  extensive  paper  on  the  geology  of  this  region  was 
published  by  Edward  Hitchcock  in  1823,*  then  just  thirty 
years  of  age.  This  paper  shows  the  evidence  of  exten- 
sive field  observations,  and  his  comments  in  regard  to 
the  trap  and  granite  are  of  interest.  Hitchcock  gives 
^ve  pages  to  the  subject  of  **  Greenstone  Dykes  in  Old 
Red  Sandstone"  (6,  56-60,  1823)  and  makes  the  follow- 
ing statements : 

"Professor  Silliman  conducted  me  to  an  interesting  locality 
of  these  in  East-Haven.  They  occur  on  the  main  road  from 
New-Haven  to  East-Haven,  less  than  half  a  mile  from  Tomlin- 
son's  bridge    .    .    .    (p.  56). 

They  are  an  interesting  feature  in  our  geology,  and  deserve 
more  attention ;  and  it  is  peculiarly  fortunate  that  they  should 
be  situated  so  near  a  geological  school  and  the  first  mineral 
cabinet  in  our  country    .    .    .    (p.  58). 

Origin  of  Greenstone. 

Does  the  greenstone  of  the  Connecticut  afford  evidence  in 
favour  of  the  Wernerian  or  of  the  Huttonian  theory  of  its 
origin?  Averse  as  I  feci  to  taking  a  side  in  this  controversy,  I 
cannot  but  say,  that  the  man  who  maintains,  in  its  length  and 
breadth,  the  original  hypothesis  of  Werner  in  regard  to  the 
aqueous  deposition  of  trap,  will  find  it  for  his  interest,  if  he 
wishes  to  keep  clear  of  doubts,  not  to  follow  the  example  of 
D'Aubuisson,  by  going  forth  to  examine  the  greenstone  of  this 
region,  lest,  like  that  geologist,  he  should  be  compelled,  not  only 
to  abandon  his  theory,  but  to  write  a  book  against  it.  Indeed, 
when  surveying  particular  portions  of  this  rock,  I  have  some- 
times thought  Bakewell  did  not  much  exaggerate  when  he  said 
in  regard  to  Werner's  hypothesis,  that,  'it  is  hardly  possible 
for  the  human  mind  to  invent  a  system  more  repugnant  to 
existing  facts.' 

On  the  other  hand,  the  Huttonian  would  doubtless  have  his 
heart  gladdened,  and  his  faith  strengthened  by  a  survey  of  the 
greater  part  of  this  rock.  As  he  looked  at  the  dikes  of  the  old 
red  sandstone,  he  would  almost  see  the  melted  rock  forcing  its 
way  through  the  fissures ;  and  when  he  came  to  the  amygdaloi- 
dal,  especially  to  that  variety  which  resembles  lava,  he  might 
even  be  tempted  to  apply  his  thermometer  to  it,  in  the  suspicion 
that  it  was  not  yet  quite  cool    .    .    .    (p.  59). 

By  treating  the  subject  in  this  manner  I  mean  no  disrespect 
to  any  of  the  distinguished  men  who  have  adopted  either  side  of 


KNOWLEDGE  OF  EAETH  STRUCTURE     161 

this  question.  To  President  Cooper  especially,  who  regards  the 
greenstone  of  the  Connecticut  as  volcanic,  I  feel  much  indebted 
for  the  great  mass  of  facts  he  has  collected  on  the  subject.  And 
were  I  to  adopt  any  hypothesis  in  regard  to  the  origin  of  our 
greenstone,  it  would  be  one  not  much  different  from  his''  (p.  60). 

By  1833  and  more  clearly  in  1841  Hitchcock  had  come 
to  recognize  the  distinction  between  intrusive  and  extru- 
sive basaltic  sheets  in  the  Connecticut  valley.  Dawson 
also  came  to  regard  the  Acadian  sheets  as  extrusive,  and 
Emerson  in  1882  recalled  again  the  evidence  for  Massa- 
chusetts (24,  195,  1882).  Davis,  however,  went  a  step 
further  and  by  applying  distinctive  criteria  not  only  sep- 
arated intrusive  and  extrusive  sheets  throughout  the 
whole  TriassLc  area,  but  by  using  basalt  flows  as  strati- 
graphic  horizons  unraveled  for  the  first  time  the  system 
of  faults  which  cut  the  Triassic  system.  His  preliminary 
paper  (24,  345,  1882)  was  followed  by  many  others. 

From  1880  onward  begins  the  period  of  precise  struc- 
tural field  work.  The  older  geologists  mostly  conceived 
their  work  after  reconnaissance  methods.  From  1870  to 
1880  a  group  of  younger  men  entered  geology  who  paid 
close  attention  to  the  solid  geometry  and  mechanics  of 
earth  structures.  In  their  hands  physical  and  dynamical 
geology  began  to  assume  the  standing  of  a  precise  and 
quantitative  science.  In  the  field  of  intrusive  rocks  the 
opening  classic  was  by  Gilbert,  who  in  his  volume  on  the 
geology  of  the  Henry  Mountains,  published  in  1880,  made 
laccoliths  known  to  the  world.  With  the  beginning  of 
this  new  period  we  may  well  leave  the  subject  of  intru- 
sive rocks  and  turn  to  the  progress  of  knowledge  in 
regard  to  those  deeper  and  vaster  bodies  now  known  as 
batholiths.  These,  since  erosion  does  not  expose  their 
bottoms,  Daly  separates  from  intrusives  and  classifies  as 
subjacent.  The  batholiths  consist  typically  of  granite 
and  granodiorite,  and  introduce  us  to  the  problem  of 
granite. 

Views  on  the  Structural  Relations  of  Granite, 

Conscientious  field  observations  were  sufficient  to 
establish  the  true  nature  of  the  intrusive  and  extrusive 
rocks.     The  case  was  very  different,  however,  with  the 


162  A  CENTURY  OF  SCIENCE 

nature  and  relations  of  the  great  bodies  of  granite, 
which  may  be  taken  in  the  structural  sense  as  including 
all  the  visibly  crystalline  acidic  and  intermediate  rocks, 
known  more  specifically  as  granite,  syenite,  and  diorite. 

The  large  bodies  of  granite,  structurally  classified  as 
stocks,  or  batholiths,  commonly  show  wedges,  tongues,  or 
dike  networks  cutting  into  the  surrounding  rocks.  The 
relations,  however,  are  not  all  so  simple  as  this.  Gran- 
ites may  cover  vast  areas,  they  are  usually  the  older 
rocks,  they  are  generally  associated  with  regional 
metamorphism  of  the  intruded  formations,  which  meta- 
morphism  is  now  understood  to  be  due  chiefly  to  the  heat 
and  mineralizers  given  off  from  the  granite  magma,  asso- 
ciated with  mashing  and  shearing  of  the  surrounding 
rocks.  The  granite  was  often  injected  in  successive 
stages  which  alternated  with  the  stages  of  regional  mash- 
ing. A  parallel  or  gneissic  structure  is  thus  developed 
which  is  in  part  due  to  mashing,  in  part  to  igneous  injec- 
tion. Where  the  ascent  of  heat  into  the  cover  is  exces- 
sive, or  where  blocks  are  detached  and  involved  in  the 
magma,  the  latter  may  dissolve  some  of  the  older  cover 
rocks,  even  where  these  were  of  sedimentary  origin. 

Thus  between  mashing,  injection,  and  assimilation  the 
genetic  relationships  of  a  batholith  to  its  surroundings 
are  in  many  instances  obscure.  Nevertheless,  attention 
to  the  larger  relations  shows  that  the  molten  magma  orig- 
inated at  great  depths  in  the  earth's  crust,  far  below  the 
bottoms  of  geosynclines,  and  consists  of  primary  igneous 
material,  not  of  fused  sediments.  From  those  depths  it 
has  ascended  by  various  processes  into  the  outer  crust, 
where  it  crystallized  into  granite  masses,  to  be  later 
exposed  by  erosion.  The  amount  of  material  which  can 
be  dissolved  and  assimilated  must  be  small  in  compari- 
son with  the  whole  body  of  the  magma.  The  original 
composition  of  the  magma  was  probably  basic,  nearer 
that  of  a  basalt  than  that  of  a  granite.  Differentiation 
of  the  molten  mass  is  thought  to  cause  the  upper  and 
lower  parts  of  the  chamber  to  become  unlike,  the  lighter 
and  more  acidic  portion  giving  rise  to  the  great  bodies  of 
granite.  With  the  exception  of  certain  border  zones  the 
whole,  however,  is  regarded  as  igneous  rock  risen  from 
the  depths. 


KNOWLEDGE  OF  EARTH  STRUCTURE     163 

The  complex  border  relations,  but  more  particularly 
certain  academic  hypotheses,  led  to  a  period  of  misunder- 
standing and  retrogression  in  regard  to  the  nature  of 
granites.  It  constitutes  an  interesting  illustration  of 
the  possibility  of  a  wrong  theory  leading  interpretation 
astray,  chiefly  through  the  magnification  of  minor  into 
major  factors.  This  history  illustrates  the  dangers  of 
qualitative  science  as  compared  to  quantitative,  of  a 
single  hypothesis  as  matched  against  the  method  of  mul- 
tiple working  hypothesis.  This  flux  of  opinion  in  regard 
to  the  nature  of  granites  may  be  traced  through  the  vol- 
umes of  the  Journal. 

E.  Hitchcock  in  1824  (6,  12)  noted  that  in  places  gran- 
ite appeared  bedded,  but  in  other  places  existed  in  veins 
which  cut  obliquely  across  the  strata.  Silliman,  although 
careful  not  to  deny  the  aqueous  origin  of  some  basalts, 
yet  held  that  the  field  evidence  of  New  England  indicates 
for  that  region  the  igneous  or  Huttonian  origin  of  trap 
and  granite  (7,  238, 1824). 

In  1832  the  following  article  by  Hitchcock  appeared  in 
the  Journal  (22,  1,  70) : 

Eeport  on  the  Geology  of  Massachusetts ;  examined  under  the 
direction  of  the  Government  of  that  State,  during  the  years 
1830  and  1831;  by  Edward  Hitchcock,  Prof,  of  Chemistry  and 
Natural  History  in  Amherst  College. 

A  footnote  adds  that  this  is  **  published  in  this  Journal  by 
consent  of  the  Government  of  Massachusetts,  and  intended  to 
appear  also  in  a  separate  form,  and  to  be  distributed  among  the 
members  of  the  Legislature  of  the  same  State,  about  the  time 
of  its  appearance  in  this  work.  It  is,  we  believe,  the  first  exam- 
ple in  this  country,  of  the  geological  survey  of  an  entire  State. ' ' 

This  article  includes  a  geological  map  of  the  state  and 
covers  the  subject  of  economic  geology.  The  report 
brought  forth  the  following  remarks  from  a  French 
reviewer  in  the  Revue  Encyclopedique,  Aug.  1832,  quoted 
in  the  Journal  (23,  389, 1833) : 

**A  single  glance  at  this  report,  is  sufficient  to  convince  any 
one  of  the  utility  of  such  a  work,  to  the  state  which  has  under- 
taken it ;  and  to  regret  that  there  is  so  very  small  a  part  of  the 
French  territory,  whose  geological  constitution  is  as  well  known 
to  the  public,  as  is  now  the  state  of  Massachusetts.  France  has 
the  greater  cause  to  regret  her  being  distanced  in  this  race  by 


164  A  CENTURY  OF  SCIENCE 

America,  from  her  having  a  corps  of  mining  engineers,  who 
if  they  had  the  means,  would,  in  a  very  short  time  furnish  a 
work  of  the  same  kind,  still  more  complete,  of  each  of  the 
departments. ' ' 

The  complete  report  published  in  1833  is  a  work  of  700 
pages.  Pages  465  to  517  are  devoted  to  the  subject  of 
granite.  Numerous  detailed  sketches  are  given  showing 
contact  relations.  Nine  pages  are  given  to  theoretical 
considerations  and  many  lines  of  proof  are  given  that 
granite  is  an  igneous  rock,  molten  from  the  internal  heat 
of  the  earth,  and  intruded  into  the  sedimentary  strata. 
His  statement  is  the  clearest  published  in  the  world,  so 
far  as  the  writer  is  aware,  up  to  that  date,  and  marks 
Edward  Hitchcock  as  one  of  the  leading  geologists  of  his 
generation  in  Europe  as  well  as  America.  Unfortu- 
nately his  views  were  largely  lost  to  sight  during  the  fol- 
lowing generation. 

In  1840  the  first  American  edition  of  MantelPs  Won- 
ders of  Geology  gave  currency  to  the  idea  that  granite  is 
proved  to  be  of  all  geological  ages  up  to  the  Tertiary 
(39,  6,  1840).  In  1843  J.  D.  Dana  pointed  out  (45,  104) 
that  schistosity  was  no  evidence  of  sedimentary  origin. 
He  regarded  most  granites  as  igneous  as  shown  by  their 
structural  relations,  but  considers  that  some  may  have 
had  a  sedimentary  origin. 

Rise  and  Decline  of  the  Metamorphic  Theory  of  Chranite, 

Up  to  1860  granite  was  regarded  on  the  basis 
of  the  facts  of  the  field  as  essentially  an  intrusive 
rock,  but  gneiss  as  a  metamorphic  product  mostly  of  sedi- 
mentary origin.  It  seemed  as  though  sound  methods  of 
research  and  interpretation  were  securely  established. 
Nevertheless,  a  new  era  of  speculation  and  a  modified 
Wernerism  arose  at  that  time  with  a  paper  by  T.  Sterry 
Hunt,  marking  a  retrogression  in  the  theory  of  granite 
which  lasted  until  his  death  in  1892. 

In  November,  1859,  Hunt  read  before  the  Geological 
Society  of  London  a  paper  on  *^Some  Points  in  Chemical 
Geology '^  in  which  he  announced  that  igneous  rocks  are 
in  all  cases  simply  fused  and  displaced  sediments,  the 
fusion  taking  place  by  the  rise  of  the  earth's  internal 


KNOWLEDGE  OF  EARTH  STRUCTURE     165 

heat  into  deeply  buried  and  water-soaked  masses  of  sedi- 
ments (see  30,  133,  1860).  The  germ  of  this  idea  of 
aqueo-igneous  fusion  was  far  older,  due  to  Babbage  and 
John  Herschel,  neither  of  them  geologists,  but  such 
sweeping  extensions  of  it  had  never  before  been  pub- 
lished. Hunt  had  the  advantage  of  a  wide  acquaintance- 
ship with  geological  literature  and  chemistry.  He  wrote 
plausibly  on  chemical  and  theoretical  geology,  but  his 
views  were  not  controlled  by  careful  field  observations. 
In  fact  he  wrote  confidently  on  regions  which  apparently 
he  had  never  seen  and  where  a  limited  amount  of  field 
work  would  have  shown  him  to  have  been  fundamentally 
in  error.  A  man  of  egotistical  temperament,  he  sought 
to  establish  priority  for  himself  in  many  subjects  and  in 
order  to  cover  the  field  made  many  poorly  founded  asser- 
tions. Building  on  to  another  Wernerian  idea,  he  held 
that  many  metamorphic  minerals  had  a  chronologic  value 
comparable  to  fossils — staurolite  for  example  indicating 
a  pre-Silurian  age — and  on  this  basis  divided  the  crystal- 
line rocks  into  five  series.  Although  there  is  much  of 
value  buried  in  Hunt's  work  it  is  difficult  to  disentangle 
it,  with  the  result  that  his  writings  were  a  disservice  to 
the  science  of  geology.  Although  carrying  much  weight 
in  his  lifetime,  they  have  passed  with  his  death  nearly 
into  oblivion. 

Marcou,  with  a  limited  knowledge  of  American  geol- 
ogy, and  but  little  respect  for  the  opinions  of  others,  had 
published  a  geologic  map  of  the  United  States  containing 
gross  errors.  In  support  of  his  views  he  read  in  Novem- 
ber, 1861,  a  paper  on  the  Taconic  and  Lower  Silurian 
Rocks  of  Vermont  and  Canada.  In  the  following  year 
he  was  severely  reviewed  by  **T,"  who  states  positively 
in  controverting  Marcou  (33,  282,  283,  1862)  that  **the 
granites  (of  the  Green  Mountains)  are  evidently  strata 
altered  in  place." 

*'Mr.  Marcou  should  further  be  informed  that  the  granites 
of  the  Alpine  summits,  instead  of  being,  as  was  once  supposed, 
eruptive  rocks,  are  now  known  to  be  altered  strata  of  newer 
Secondary  and  Tertiary  ag^.  A  simple  structure  holds  good  in 
the  British  Islands,  where  as  Sir  Roderick  Murchison  has  shown 
in  his  recent  Geological  map  of  Scotland,  Ben  Nevis  and  Ben 
Lawers  are  found  to  be  composed  of  higher  strata,  lying  in 


166  A  CENTURY  OF  SCIENCE 

synclinals.  This  great  law  of  mountain  structure  would  alone 
lead  us  to  suppose  that  the  gneiss  of  the  Green  mountains, 
instead  of  being  at  the  base,  is  really  at  the  summit  of  the  series. 

We  cannot  here  stop  to  discuss  Mr.  Marcou's  remark  about 
'the  unstratified  and  oldest  crystalline  rocks  of  the  White 
mountains'  which  he  places  beneath  the  lower  Taconic  series. 
Mr.  Lesley  has  shown  that  these  granites  are  stratified,  and  with 
Mr.  Hunt,  regards  them  as  of  Devonian  Age.  (This  Journal, 
vol.  31,  p.  403.)  Mr.  Marcou  has  come  among  us  with  notions 
of  mountains  upheaved  by  intrusive  granites,  and  similar  anti- 
quated traditions,  now,  happily  for  science,  well  nigh  forgotten. ' ' 

It  is  seen  that  Marcou,  notwithstanding  the  general 
character  of  his  work,  happened  to  be  nearer  right  in 
some  matters  than  were  his  critics,  and  that  <*T''  had 
adopted  to  the  limit  the  views  of  Hunt. 

The  recovery  of  geology  from  this  period  of  confusion 
was  partly  owing  to  the  slow  accumulation  of  opposed 
facts;  especially  to  a  recognition  of  the  fact  that  the 
overplaced  relation  of  the  granite  gneisses  in  western 
Scotland  was  due  to  great  overthrusts ;  also  to  the  evi- 
dence of  the  clearly  intrusive  nature  of  many  of  the 
Cordilleran  granites.  The  recovery  of  a  sounder  theory 
was  hastened,  however,  by  the  application  of  criticisms 
by  J.  D.  Dana  in  the  Journal.  In  1866  (42,  252)  Dana 
pointed  out  that  sedimentary  rocks  in  Pennsylvania,  in 
Nova  Scotia,  and  other  regions  which  had  been  buried  to 
a  depth  of  at  least  16,000  feet  are  not  metamorphic. 
Mere  depth  of  burial  of  sediments  was  not  sufficient 
therefore  to  produce  metamorphism  and  aqueo-igneous 
fusion.  The  baseless  and  speculative  character  of  the 
use  of  minerals  as  an  index  of  age  and  of  Hunt's  inter- 
pretation of  New  England  geology  in  general  was  shown 
by  Dana  in  1872  (3,  91).  The  following  year  Dana 
pointed  out  clearly  that  igneous  eruptions  in  general 
have  been  derived  from  a  deep-seated  source  and  did  not 
come  from  the  aqueo-igneous  fusion  of  sediments.  As  to 
gradations  between  true  igneous  rocks  and  fused  and 
displaced  sediments  he  makes  the  following  statements 
(6, 114, 1873) : 

''Again,  the  plastic  rock-material  that  may  be  derived  from 
the  fusion  or  semifusion  of  the  supercrust,   (that  is,  of  rocks 


KNOWLEDGE  OF  EABTH  STRUCTURE     167 

originally  of  sedimentary  origin,)  gives  rise  to  ** igneous *'  rocks 
often  not  distinguishable  from  other  igneous  rocks,  when  it  is 
ejected  through  fissures  far  from  its  place  of  origin ;  while  crys- 
talline rocks  are  simply  metamorphic  if  they  remain  in  their 
original  relations  to  the  associated  rocks,  or  nearly  so. 

Between  these  latter  igneous  rocks  and  the  metamorphic  there 
may  be  indefinite  gradations,  as  claimed  by  Hunt.  But  if  our 
reasonings  are  right,  the  great  part  of  igneous  rocks  can  be 
proved  to  have  had  no  such  supercrust  origin.  The  argument 
from  the  presence  of  moisture  or  of  hydrous  minerals  in  such 
rocks  in  favor  of  their  origin  from  the  fusion  of  sediments  has 
been  shown  to  be  invalid. ' ' 

The  injected  marginal  rocks  and  the  post-intrusive 
metamorphism  of  most  of  the  New  England  granites  has, 
however,  obscured  more  or  less  their  real  igneous  nature 
so  that  the  gradation  from  metamorphic  sediments 
through  igneous  gneisses  to  granites  could  be  read  in 
either  direction.  These  features  misled  Dana  who 
accepted  the  prevailing  idea  of  the  general  metamorphic 
origin  of  granite.  Dana  makes  the  following  statement 
(6,  164,  1873) : 

**But  Hunt  is  right  in  holding  that  in  general  granite  and 
syenite  (the  quartz-bearing  syenite)  are  undoubtedly  meta- 
morphic rocks  where  not  vein-formations,  as  I  know  from  the 
study  of  many  examples  of  them  in  New  England;  and  the 
veins  are  results  of  infiltration  through  heated  moisture  from 
the  rocks  adjoining  some  part  of  the  opened  fissures  they  fill." 

Granite,  although  regarded  at  this  time  as  the  extreme 
of  the  metamorphic  series  and  originating  from  sedi- 
ments, was  looked  upon  as  typically  Archean  in  age, 
though  in  some  cases  younger.  Such  a  doctrine  per- 
mitted such  extreme  misinterpretations  as  that  of 
Clarence  King  and  S.  F.  Emmons  on  the  nature  of  the 
intrusive  granite  of  the  Little  Cottonwood  canyon  in  the 
Wahsatch  Range.  This  body  cuts  across  30,000  feet  of 
Paleozoic  rocks  and  to  the  careful  observer,  as  later 
admitted  by  Emmons,  shows  clear  evidence  of  its  trans- 
gressive  nature.  But  at  that  time  it  was  generally  con- 
sidered that  granite  mountains  were  capable  of  resist- 
ing the  erosion  of  all  geological  time.  Consequently  it 
did  not  seem  incredible  to  King  and  his  associates  that 
here  a  great  granite  range  of  Archean  origin  had  stood 


168  A  CENTURY  OF  SCIENCE 

up  through  Paleozoic  time  until  gradual  subsidence  had 
permitted  it  to  be  buried  beneath  30,000  feet  of  sedi- 
ments.^ 

It  may  seem  to  the  present  day  reader  that  such  a  mis- 
interpretation, doing  violence  to  fundamental  geologic 
knowledge  as  now  recognized,  was  inexcusable;  but  in 
the  light  of  the  history  of  geology  as  here  detailed  it  is 
seen  to  have  been  the  interpretation  natural  to  that  time. 
It  is  true  that  a  careful  examination  of  the  facts  of  that 
very  field  would  have  proved  the  post-Paleozoic  and  in- 
trusive nature  of  that  great  granite  body  now  known 
as  the  Little  Cottonwood  batholith,  but  Emmons  has 
explained  the  rapid  and  partial  nature  of  the  observa- 
tions which  they  were  compelled  to  make  in  order  to  keep 
up  to  their  schedule  of  progress  (16,  139,  1903). 

"Whitney  had  found  some  years  earlier  that  the  gran- 
ites of  the  Sierra  Nevada  were  igneous  rocks  intrusive 
into  the  Triassic  and  Jurassic  strata.  The  Lake  Supe- 
rior geologists  began  to  show  in  the  eighties  that  granite 
was  there  an  intrusive  igneous  rock.  R.  D.  Irving  and 
"Wadsworth  noted  these  relations.  Lawson  in  1887 
pointed  out  emphatically  (33,  473)  that  the  granites  of 
the  Rainy  Lake  region,  although  basal,  were  younger 
than  the  schists  which  lay  above  them.  The  granite- 
gneisses  he  held  were  of  clearly  the  same  igneous  origin 
as  the  granites  and  neither  gave  any  field  evidence  of 
being  fused  and  displaced  sediments.  From  this  time 
forward  the  truly  igneous  nature  of  granite  became 
increasingly  accepted  until  now  the  notion  of  its  being 
made  of  sedimentary  rocks  softened  and  recrystallized  by 
the  rise  of  the  isogeotherms  through  deep  burial  is  as 
obsolete  as  the  still  older  doctrine  of  the  Neptunists  that 
granite  was  laid  down  as  a  crystalline  precipitate  on  the 
floor  of  the  primitive  ocean. 

The  recognition  of  the  truly  igneous  nature  of  granites 
has  been  followed  in  the  present  generation  by  a  series 
of  studies  on  their  structural  relations  and  mode  of 
genesis.  A  number  of  important  initial  articles  on  vari- 
ous aspects  of  structure  and  contact  relations  have 
appeared  in  the  Journal,  but  this  sketch  of  the  history  of 
the  subject  may  well  stop  with  the  introduction  to  this 
modern  period. 


KNOWLEDGE  OP  EARTH  STRUCTURE     169 

Orogenic  Structures, 
Views  of  Flutonists  and  Neptunists» 

Orogenic  structures  are,  as  the  name  implies,  those 
connected  with  the  birth  of  mountains.  Nearly  synony- 
mous terms  are  deformative  or  secondary  structures. 
On  a  small  scale  this  division  embraces  the  phenomena 
exposed  in  the  rock  ledge  or  quarry  face,  or  in  the  dips 
and  dislocations  varying  from  one  exposure  to  another. 
These  structures  include  faults,  folds,  and  foliation.  On 
a  larger  scale  are  included  the  relations  of  the  differ- 
ent ranges  of  a  mountain  system  to  each  other,  relations 
to  previous  geologic  history,  relations  to  the  earth  as  a 
whole,  and  to  the  forces  which  have  generated  the  struc- 
tures. 

In  order  to  see  the  stage  of  development  of  this  subject 
in  1818  and  its  progress  as  reflected  through  the  publica- 
tions of  a  century,  more  particularly  in  the  Journal,  it 
is  desirable  to  turn  again  to  those  two  treatises  emanat- 
ing from  Edinburgh  at  the  beginning  of  the  nineteenth 
century  and  representing  two  opposite  schools  of 
thought,  the  Plutonists  and  Neptunists. 

Playfair,  in  1802,  devotes  nineteen  pages  to  the  subject 
of  the  inflection  and  elevation  of  strata.^  He  places 
emphasis  on  the  characteristic  parallelism  of  the  strike 
of  the  folds  throughout  a  region,  as  shown  through  the 
intersection  of  the  folds  by  a  horizontal  plane  of  erosion. 
He  contrasts  this  with  the  arches  shown  in  a  transverse 
section  and  enlarges  on  our  ability  to  study  the  deeply 
buried  strata  through  the  denudation  of  the  folded  struc- 
ture. He  argues  from  these  relations  that  the  struc- 
tures can  not  be  explained  by  the  vague  appeal  of  the 
Neptunists  to  forces  of  crystallization,  to  slopes  of  orig- 
inal deposition,  or  to  sinking  in  of  the  roofs  of  caverns. 
The  causes  he  argues  were  heat  combined  with  pressure. 
As  to  the  directions  in  which  the  pressure  acted  he  is  not 
altogether  clear,  but  apparently  regards  the  pressure  as 
acting  in  upward  thrusts  against  the  sedimentary  planes, 
the  latter  yielding  as  warped  surfaces.  His  method  of 
presentation  is  that  of  inductive  reasoning  from  facts, 
but  he  stopped  short  of  the  conception  of  horizontal  com- 
pression through  terrestrial  contraction. 


ITO  A  CENTURY  OF  SCIENCE 

Jameson,  professor  of  natural  history  in  the  same  uni- 
versity, in  1808  contemptuously  ignores  the  work  of  Hut- 
ton  and  Playfair  in  what  he  calls  the  ^^monstrosities 
known  under  the  name  of  Theories  of  the  Earth.''  In  a 
couple  of  pages  he  confuses  and  dismisses  the  whole  sub- 
ject of  deformation.     He  states  f 

*'It  is  therefore  a  fact,  that  all  inclined  strata,  with  a  very 
few  exceptions,  have  been  formed  so  originally,  and  do  not  owe 
their  inclination  to  a  subsequent  change. 

When  we  examine  the  structure  of  a  mountain,  we  must  be 
careful  that  our  observations  be  not  too  micrological,  otherwise 
we  shall  undoubtedly  fail  in  acquiring  a  distinct  conception  of 
it.  This  will  appear  evident  when  we  reflect  that  the  geognostic 
features  of  Nature  are  almost  all  on  the  great  scale.  In  no  case 
is  this  rule  to  be  more  strictly  followed  than  in  the  examination 
of  the  stratified  structure. 

By  not  attending  to  this  mode  of  examination,  geognosts 
have  fallen  into  numberless  errors,  and  have  frequently  given 
to  extensive  tracts  of  country  a  most  irregular  and  confused 
structure.  Speculators  building  on  these  errors  have  repre- 
sented the  whole  crust  of  the  globe  as  an  irregular  and  unseemly 
mass.  It  is  indeed  surprising,  that  men  possessed  of  any  knowl- 
edge of  the  beautiful  harmony  that  prevails  in  the  structure  of 
organic  beings  could  for  a  moment  believe  it  possible,  that  the 
great  fabric  of  the  globe  itself, — that  magnificent  display  of 
Omnipotence, — should  be  destitute  of  all  regularity  in  its  struc- 
ture, and  be  nothing  more  than  a  heap  of  ruins." 

This  was  the  attitude  of  a  leader  of  British  opinion 
toward  the  subject  of  deformational  geology  from  which 
the  infant  science  had  to  recover  before  progress  could  be 
made.  The  early  maps  were  essentially  mineralogical 
and  lithological.  The  order  of  superposition  and  the 
consequent  sequence  of  age  was  regarded  as  settled  by 
Werner  in  Germany  and  not  requiring  investigation  in 
America.  The  early  examples  of  structure  were  sections 
drawn  with  exaggerated  vertical  scales  and  those  of 
Maclure  do  not  show  detail. 

Recognition  of  Appalachian  Structures, 

Following  the  founding  of  the  Journal  in  1818  there  is 
observable  a  growth  in  the  quality  and  detail  of  geologi- 
cal mapping.    Dr.  Aiken,  professor  of  natural  philosophy 


KNOWLEDGE  OF  EARTH  STRUCTURE     171 

and  chemistry  in  Mt.  St.  Mary's  College,  published  in  the 
Journal  in  1834  (26,  219)  a  vertical  section  extending 
between  Baltimore  and  Wheeling,  a  distance  of  nearly 
250  miles,  on  a  scale  of  about  7  miles  per  inch.  The  suc- 
cession of  rocks  is  carefully  shown  and  the  direction  of 
dip,  but  no  attempt  is  made  to  show  the  underground 
relations,  the  stratigraphic  sequence,  and  the  folded 
structures  which  are  so  clear  in  that  Appalachian  section. 
The  text  also  shows  that  the  author  had  not  recognized 
the  folded  structure.  Furthermore,  where  the  folds 
cease  at  the  Alleghany  mountain  front,  the  flat  strata  are 
shown  as  resting  unconformably  on  the  folded  rocks  to 
the  east. 

R.  C.  Taylor,  geologist,  civil  and  mining  engineer,  was 
from  1830  to  1835  the  leading  student  of  Pennsylvanian 
geology  as  shown  by  the  publication  in  1835  of  four 
papers  aggregating  over  80  pages  in  the  Transactions  of 
the  Geological  Society  of  Pennsylvania.  His  work  is 
noticeable  for  accuracy  in  detail  and  no  doubt  was  influ- 
ential in  setting  a  high  standard  for  the  state  geological 
survey  which  immediately  followed. 

H.  D.  and  W.  B.  Rogers  have  been  given  credit  in  this 
country,  and  in  Europe  also,  as  being  the  leading 
expounders  of  Appalachian  structure.  Merrill  speaks  of 
H.  D.  Rogers  as  unquestionably  the  leading  structural 
geologist  of  his  time.^  To  the  writer,  this  attributed 
position  appears  to  be  due  to  his  opportunities  rather 
than  to  scientific  acumen.  The  magnificent  but  readily 
decipherable  folded  structure  of  Pennsylvania,  the  rela- 
tionships of  coal  and  iron  to  this  structure,  the  consid- 
erable sums  of  money  appropriated,  and  the  work  of  a 
corps  of  able  assistants  were  factors  which  made  it  com- 
paratively easy  to  reach  important  results.  In  ability  to 
weigh  facts  and  interpret  them  Edward  Hitchcock 
showed  much  more  insight  than  H.  D.  Rogers,  while  in 
the  philosophic  and  comprehensive  aspects  of  the  subject 
J.  D.  Dana  far  outranks  him. 

H.  D.  Rogers  in  his  first  report  on  the  geological  sur- 
vey of  New  Jersey,  1836,  recognizes  that  the  Cambro- 
Silurian  limestones  (lower  Secondary  limestones)  were 
deposited  as  nearly  horizontal  beds  and  the  ridges  of 
pre-Cambrian  gneiss  (Primary)  had  been  pushed  up  as 


172  A  CENTURY  OF  SCIENCE 

anticlinal  axes  (p.  128).  He  also  clearly  recognized  the 
distinction  between  slaty  cleavage  and  true  dip  as  shown 
in  the  Ordovician  slates  (p.  97).  Between  1836  and  1840 
he  had  learned  a  great  deal  on  the  nature  of  folds  as  is 
shown  in  his  Pennsylvania  report  for  1839  and  the  struc- 
ture sections  in  his  New  Jersey  report  for  1840. 

R.  C.  Taylor,  who  had  now  become  president  of  the 
board  of  directors  of  the  Dauphin  and  Susquehanna  Coal 
Company,  published  in  the  Journal  in  1841  (41,  80)  an 
important  paper  entitled  **  Notice  of  a  Model  of  the 
Western  portion  of  the  Schuylkill  or  Southern  Coal 
Field  of  Pennsylvania,  in  illustration  of  an  Address  to 
the  Association  of  American  Geologists,  on  the  most 
appropriate  modes  for  representing  Geological  Phe- 
nomena.'' In  this  paper  he  calls  attention  to  the  value 
of  modeling  as  a  means  of  showing  true  relations  in  three 
dimensions.  He  condemns  the  custom  prevalent  among 
geologists  of  showing  structure  sections  with  an  exag- 
gerated vertical  scale  with  its  resultant  topographic  and 
structural  distortions.  Taylor  was  widely  acquainted 
with  the  structure  of  Pennsylvania,  Maryland,  and  Vir- 
ginia. 

Nature  of  Forces  Producing  Folding, 

In  1825  Dr.  J.  H.  Steele  sent  to  Professor  Silliman  two 
detailed  drawings  and  description  of  an  overturned  fold 
at  Saratoga  Lake,  New  York.  As  to  the  significance  of 
this  feature  Steele  makes  the  following  statement  (9,  3, 
1825) : 

**It  is  impossible  to  examine  this  locality  without  being 
strongly  impressed  with  the  belief  that  the  position  which  the 
strata  here  assume  could  not  have  been  effected  in  any  other 
way  than  by  a  power  operating  from  beneath  upwards  and  at 
the  same  time  possessing  a  progressive  force ;  something  analo- 
gous to  what  takes  place  in  the  breaking  up  of  the  ice  of  large 
rivers.  The  continued  swelling  of  the  stream  first  overcomes 
the  resistance  of  its  frozen  surface  and  having  elevated  it  to  a 
certain  extent,  it  is  forced  into  a  vertical  position,  or  thrown 
over  upon  the  unbroken  stratum  behind,  by  the  progressive 
power  of  the  current.'' 

So  far  as  the  present  writer  is  aware  this  is  the  first 
recognition  in  geological  literature  of  the  evidence  of  a 


KNOWLEDGE  OF  EARTH  STEUCTURE     173 

horizontally  compressive  and  overturning  force  as  a 
cause  of  folding. 

To  E.  Hitchcock  belongs  the  credit  of  being  the  first  to 
describe  overturning  and  inversion  of  strata  on  a  large 
scale,  but  without  clearly  recognizing  it  as  such.  In 
western  Massachusetts  metamorphism  is  extreme  in  the 
lower  Paleozoic  rocks  in  the  vicinity  of  the  overthrust 
mass  of  Archean  granite-gneiss  which  constitutes  the 
Hoosic  range.  The  Paleozoic  rocks  of  the  valley  to  the 
west  are  overturned  and  appear  to  dip  beneath  the  older 
rocks.  Farther  west  the  metamorphism  fades  out  and 
the  series  assumes  a  normal  position.  Such  an  inverted 
relation,  up  to  that  time  unknown,  is  described  in  1833  as 
follows  by  Hitchcock  in  his  Geology  of  Massachussetts 
(pp.  297,  298) : 

*'But  a  singular  anomaly  in  the  superposition  of  the  series  of 
rocks  above  described,  presents  a  great  difficulty  in  this  case. 
The  strata  of  these  rocks  almost  uniformly  dip  to  the  east :  that 
is,  the  newer  rocks  seem  to  crop  out  beneath  the  older  ones ;  so 
that  the  saccharine  limestone,  associated  with  gneiss  in  the  east- 
ern part  of  the  range,  seems  to  occupy  the  uppermost  place  in 
the  series.  Now  as  superposition  is  of  more  value  in  determin- 
ing the  relative  ages  of  rocks  than  their  mineral  characters,  must 
we  not  conclude  that  the  rocks,  as  we  go  westerly  from  Hoosac 
mountain,  do  in  fact  belong  to  older  groups  ?  The  petrifactions 
which  some  of  them  contain,  and  their  decidedly  fragmentary 
character,  will  not  allow  such  a  supposition  to  be  indulged  for 
a  moment.  It  is  impossible  for  a  geologist  to  mistake  the  evi- 
dence, which  he  sees  at  almost  every  step,  that  he  is  passing 
from  older  to  newer  formations,  just  as  soon  as  he  begins  to 
cross  the  valley  of  Berkshire  towards  the  west.  We  are  driven 
then  to  the  alternative  of  supposing,  either  that  there  must  be 
a  deception  in  the  apparent  outcrop  of  the  newer  rocks  from 
beneath  the  older,  or  that  the  whole  series  of  strata  has  been 
actually  thrown  over,  so  as  to  bring  the  newest  rocks  at  the  bot- 
tom. The  latter  supposition  is  so  improbable  that  I  cannot  at 
present  admit  it.'* 

Hitchcock  tried  to  reconcile  the  evidence  by  a  series  of 
unconformities  and  inclined  deposition,  but  finds  the  solu- 
tion unsatisfactory. 

In  this  same  year,  1833,  Elie  de  Beaumont,  a  dis- 
tinguished French  geologist,  published  his  theory  of  the 
origin  of  mountains.     He  advanced  the  idea  that  since 

11 


174  A  CENTURY  OF  SCIENCE 

the  globe  was  cooling  it  was  condensing,  and  the  crust, 
already  cool,  must  suffer  compression  in  adjusting  itself 
to  the  shrinking  molten  interior.  He  concluded  from  the 
evidence  shown  in  Europe  that  the  collapse  of  the  crust 
occurred  violently  and  rapidly  at  widely  spaced  intervals 
of  time.  This  hypothesis  introduced  the  idea  of  moun- 
tain folding  by  horizontal  compressive  forces.  The  the- 
oretical paper  of  de  Beaumont,  together  with  further 
observations  by  Hitchcock  and  others,  led  the  latter  in 
1841  to  a  final  belief  in  the  inversion  of  strata  on  a  large 
scale  by  horizontal  compression.  His  conclusions  are 
expressed  in  an  important  paper  published  in  the  Journal 
(41,  268,  1841)  and  given  on  April  8,  1841,  as  the  First 
Anniversary  Presidential  Address  before  the  Associa- 
tion of  American  Geologists.  This  comprehensive  sum- 
mary of  American  geology  occupies  43  pages.  Three 
pages  are  given  to  the  inverted  structure  of  the  Appa- 
lachians from  which  the  following  paragraphs  may  be 
quoted : 

**We  have  all  read  of  the  enormous  dislocations  and  inver- 
sions of  the  strata  of  the  Alps ;  and  similar  phenomena  are  said 
to  exist  in  the  Andes.  Will  it  be  believed,  that  we  have  an 
example  in  the  United  States  on  a  still  more  magnificent  scale 
than  any  yet  described?    .    .    . 

Let  us  suppose  the  strata  between  Hudson  and  Connecticut 
rivers,  while  yet  in  the  plastic  state,  (and  the  supposition  may 
be  extended  to  any  other  section  across  this  belt  of  country  from 
Canada  to  Alabama,)  and  while  only  slightly  elevated,  were 
acted  upon  by  a  force  at  the  two  rivers,  exerted  in  opposite 
directions.  If  powerful  enough,  it  might  cause  them  to  fold 
up  into  several  ridges ;  and  if  more  powerful  along  the  western 
than  the  eastern  side,  they  might  fall  over  so  as  to  take  an 
inverted  dip,  without  producing  any  remarkable  dislocations, 
while  subsequent  denudation  would  give  to  the  surface  its 
present  outline.    .    .    . 

Fourthly,  we  should  readily  admit  that  such  a  plication  and 
inversion  of  the  strata  might  take  place  on  a  small  scale.  If  for 
instance,  we  were  to  press  against  the  extremities  of  a  series  of 
plastic  layers  two  feet  long,  they  could  easily  be  made  to  assume 
the  position  into  which  the  rocks  under  consideration  are  thrown. 
Why  then  should  we  not  be  equally  ready  to  admit  that  this 
might  as  easily  be  done,  over  a  breadth  of  fifty  miles,  and  a 
length  of  twelve  hundred,  provided  we  can  find  in  nature,  forces 


KNOWLEDGE  OF  EARTH  STEUCTURE     176 

sufficiently  powerful?     Finally,  such  forces  do  exist  in  nature, 
and  have  often  been  in  operation.'' 

The  advanced  nature  of  these  conceptions  may  he 
appreciated  by  contrasting  them  with  those  put  forth  by 
H.  D.  and  W.  B.  Rogers  on  April  29, 1842,  before  the  third 
annual  meeting  of  the  same  body  (43,  177,  1842)  and 
repeated  by  them  before  the  British  Association  at  Man- 
chester two  months  later.  In  their  own  words,  the 
Rogers  brothers  from  their  studies  on  the  folds  shown  in 
Pennsylvania  and  Virginia,  conceived  mountain  folds  in 
general  to  be  produced  by  much  elastic  vapor  escaping 
through  many  parallel  fissures  formed  in  succession,  pro- 
ducing violent  propulsive  wave  oscillations  on  the  sur- 
face of  the  fluid  earth  beneath  a  thin  crust.  Thus  actual 
billows  are  assumed  to  have  rolled  along  through  the 
crust.  They  did  not  think  tangential  pressure  alone 
could  produce  folds.  Such  pressures  were  regarded  as 
secondary,  produced  by  the  propagation  of  the  waves  and 
the  only  expression  of  tangential  forces  which  they 
admitted  was  to  fix  the  folds  and  hold  them  in  position 
after  the  violent  oscillation  had  subsided  (44,  360,  1843). 
The  leading  British  geologists  De  la  Beche  and  Sedg- 
wick criticized  adversely  this  remarkable  theory,  stating 
that  they  could  see  no  such  analogy  in  mountain  folds  to 
violent  earthquake  waves  and  that  in  their  opinion  the 
slow  application  of  tangential  force  was  sufficient  to 
account  for  the  phenomena  (44,  362-365, 1843). 

H.  D.  Rogers  in  the  prosecution  of  the  geological  sur- 
vey of  Pennsylvania  displayed  notable  organizing  ability 
and  persistence  in  accomplishment,  even  to  advancing  per- 
sonally considerable  sums  of  money,  trusting  to  the  state 
legislature  to  later  reimburse  him.  Finally,  after  many 
delays  by  the  state,  the  publication  was  placed  directly 
in  his  charge  and  he  produced  in  1858  a  magnificent 
quarto  work  of  over  1,600  pages,  handsomely  illustrated, 
and  accompanied  by  an  atlas.  It  is  excellent  from  the 
descriptive  standpoint,  standing  in  the  first  class.  Meas- 
ured as  a  contribution  to  the  theory  of  dynamical  geol- 
ogy, the  explanatory  portions  were,  however,  thirty  years 
behind  the  times.  The  same  hypotheses  are  put  forth 
in  1858  as  in  1842.     There  is  no  acceptance  of  the  views 


176  A  CENTURY  OF  SCIENCE 

of  Lyell  concerning  the  nniformitarian  principles  ex- 
pounded by  this  British  leader  in  1830,  or  of  the  nature 
of  orogenic  forces  as  published  by  Elie  de  Beaumont  in 
1833.  Rogers  rejects  the  view  that  cleavage  is  due  to 
compression  and  suggests  **that  both  cleavage  and  folia- 
tion are  due  to  the  parallel  transmission  of  planes  or 
waves  of  heat,  awakening  the  molecular  forces,  and 
determining  their  direction.^  Thus  a  mere  maze  of 
words  takes  the  place  of  inductive  demonstrations 
already  published. 

In  following  the  play  of  these  opposing  currents  of 
geologic  thought  we  reach  now  the  point  where  a  period 
of  brilliant  progress  in  the  knowledge  of  mountains  and 
of  continental  structures  begins  in  the  work  of  J.  D. 
Dana.  In  1842  Dana  returned  from  the  Wilkes  Explor- 
ing Expedition  and  the  following  year  began  the  publica- 
tion of  the  series  of  papers  which  for  the  next  half 
century  marked  him  as  the  leader  in  geologic  theory  in 
America.  His  work  is  of  course  to  be  judged  against 
the  background  of  his  times.  His  papers  mark  distinct 
advances  in  many  lines  and  are  characterized  throughout 
by  breadth  of  conception  and  especially  by  clear  and  log- 
ical thinking.  His  work  was  published  very  largely  in 
the  Journal,  of  which  after  a  few  years  he  became  chief 
editor.  His  first  contribution  on  the  subject  of  moun- 
tain structures,  entitled  ^ ^ Geological  results  of  the  earth's 
contraction  in  consequence  of  cooling,''  was  published  in 
1847  (3,  176).  The  evidence  of  horizontal  pressure  was 
first  perceived  in  France  as  shown  by  the  features  of  the 
Alps.  Elie  de  Beaumont  connected  it,  by  means  of  the 
theory  of  a  cooling  and  contracting  globe,  with  the  other 
large  fact  of  the  increase  of  temperature  with  descent  in 
the  crust.  Dana  credits  the  Rogers  brothers  with  first 
making  known  the  folded  structures  of  the  Appalachians, 
but  objects  to  their  interpretation  of  origin.  He  showed 
by  means  of  diagrams  that  the  folds  are  to  be  explained 
by  lateral  pressure,  the  direction  of  overturning  indicat- 
ing the  direction  from  which  the  driving  force  proceeded. 

The  Rogers  brothers  and  especially  James  Hall,  in 
working  out  the  Appalachian  stratigraphy,  had  noted 
that  the  formations,  although  accumulating  to  a  maxi- 
mum thickness  of  between  30,000  and  40,000  feet,  showed 


KNOWLEDGE  OF  EARTH  STRUCTURE     177 

evidences  that  the  successive  formations  were  deposited 
in  shallow  water.  It  suggested  to  them  that  the  weight  of 
the  accumulating  sediments  was  the  cause  of  subsidence, 
each  foot  of  sediment  causing  a  foot  of  down  sinking. 
This  idea  has  continued  to  run  through  various  text 
books  in  geology  for  half  a  century,  yet  Dana  early 
saw  the  fallacy  and  in  1863  in  the  first  edition  of 
his  Manual  of  Geology  (p.  717)  states  ^^ whether  this 
is  an  actual  cause  or  not  in  geological  dynamics  is 
questionable. '*  In  1866  in  an  important  article  on 
*^ Observations  on  the  origins  of  some  of  the  earth's 
features,"  Dana  deals  more  fully  and  finally  with 
this  subject  (42,  205,^  252,  1866).  He  shows  that  such  an 
effect  of  accumulating  sediment  postulates  a  delicate 
balance,  a  very  thin  crust  and  no  resistance  below.  If 
such  a  weakness  were  granted  it  would  be  impossible  for 
the  earth  to  hold  up  mountains.  Furthermore  such  sub- 
sidence was  not  regular  during  its  progress  and  finally 
in  the  long  course  of  geologic  time  gave  place  to  a  reverse 
movement  of  elevation. 

Hall  had  pointed  out  the  fact  that  the  sediments  were 
thickest  on  the  east  in  the  region  of  mountain  folding  and 
thinned  out  to  a  fraction  of  this  thickness  in  the  broad 
Mississippi  basin.  Hall  argued  that  the  mere  subsidence 
of  the  trough  would  produce  the  observed  folding  and 
that  the  folding  was  unrelated  to  mountain  making  or 
crustal  shortening.  In  supposed  proof  he  cited  the  fact 
that  the  Catskills  consist  of  unfolded  rock,  are  higher 
than  the  folded  region  to  the  south,  and  nearly  as  high  as 
the  highest  metamorphic  mountains  to  the  east.^^  Hall 
and  all  his  contemporaries  were  handicapped  in  their 
geological  theories  by  a  complete  inappreciation  of  the 
importance  of  subaerial  denudation.  For  subscribing  to 
these  errors  of  their  time  even  the  ablest  men  should  not 
be  held  responsible.  Hall  was  the  most  forcible  person- 
ality in  geology  in  his  generation.  His  contributions  to 
paleontology  were  superb.  His  perception  of  the  rela- 
tion existing  between  troughs  of  thick  sediments  and 
folded  structures  was  a  contribution  of  the  first  import- 
ance; yet  in  the  structural  field  his  argument  as  to  the 
production  of  the  Appalachian. folds  by  mere  subsidence 
during  deposition  indicates   a  remarkable  inability  to 


178  A  CENTURY  OF  SCIENCE 

apply  the  logical  consequences  of  his  hypothesis  to  the 
nature  of  the  folds  as  already  made  known  by  the  Rogers. 
Dana  pointed  out  in  reply  to  Hall  that  the  folding  did  not 
correspond  to  the  requirements  of  HalPs  hypothesis, 
especially  as  the  folding  took  place  not  during,  but  after 
the  close  of  the  vast  Paleozoic  deposition.  Dana  states 
in  conclusion  on  HalPs  hypothesis  (42,  209,  1866)  that 
*  ^  It  is  a  theory  of  the  origin  of  mountains  with  the  origin 
of  mountains  left  out.'' 

The  Theory  of  Geosynclines  and  Geanticlines, 

The  fact  that  systems  of  folded  strata  lie  along  axes  of 
especially  thick  sediments  and  that  this  implied  subsi- 
dence during  deposition  was  HalPs  contribution  to  geo- 
logic theory,  but  curiously  enough  he  failed,  as  shown,  to 
connect  it  with  the  subsequent  nature  of  mountain  fold- 
ing. He  did  not  see  why  such  troughs  should  be  weak  to 
resist  horizontal  compression.  The  clear  recognition  of 
this  relationship  was  the  contribution  of  Le  Conte,  who 
in  a  paper  on  *^A  theory  of  the  formation  of  the  great 
features  of  the  earth's  surface"  (4,  345,  460,  1872), 
reached  the  conclusion  that  ^^  mountain  chains  are 
formed  by  the  mashing  together  and  the  up-swelling  of 
sea  bottoms  where  immense  thicknesses  of  sediment  have 
accumulated. ' ' 

As  to  the  cause  why  mashing  should  take  place  along 
troughs  of  thick  sediments  Le  Conte  adopts  the  hypothe- 
sis of  aqueo-igneous  fusion  proposed  independently  long 
before  by  Babbage  and  Herschel  and  elaborated  into  a 
theory  of  igneous  rocks  by  Hunt.  Under  this  view,  as  the 
older  sediments  became  deeply  buried,  the  heat  of  the 
earth's  interior  ascended  into  them,  and  since  they 
included  the  water  of  sedimentation  a  softening  and  met- 
amorphism  resulted.  Dana  had  shown,  however,  six 
years  previously  (42,  252,  1866),  as  the  following  quota- 
tion will  indicate,  that  metamorphism  of  sediments 
required  more  than  deep  burial  and  that  no  such  weaken- 
ing as  was  postulated  by  Herschel  had  occurred: 

**The  correctness  of  HerschePs  principle  cannot  be  doubted. 
But  the  question  of  its  actual  agency  in  ordinary  metamorphism. 
must  be  decided  by  an  appeal  to  facts ;  and  on  this  point  I  would 
here  present  a  few  facts  for  consideration. 


KNOWLEDGE  OF  EARTH  STRUCTURE     179 

The  numbers  and  boldness  of  the  flexures  in  the  rocks  of  most 
metamorphic  regions  have  always  seemed  to  me  to  bear  against 
the  view  that  the  heat  causing  the  change  had  ascended  by  the 
very  quiet  method  recognized  in  this  theory.    .    .    . 

But  there  are  other  facts  indicating  a  limited  sufficiency  to 
this  means  of  metamorphism.  These  are  afforded  by  the  great 
faults  and  sections  of  strata  open  to  examination.  In  the  Appa- 
lachian region,  both  of  Virginia  and  Pennsylvania,  faults  occur, 
as  described  by  the  Professors  Rogers,  and  by  Mr.  J.  P.  Lesley, 
which  afford  us  important  data  for  conclusions.  Mr.  Lesley,  an 
excellent  geologist  and  geological  observer,  who  has  explored 
personally  the  regions  referred  to,  states  that  at  the  great  fault 
of  Juniata  and  Blair  Cos.,  Pennsylvania,  the  rocks  of  the  Tren- 
ton period  are  brought  up  to  a  level  with  those  of  the  Chemung, 
making  a  dislocation  of  at  least  16,000,  and  probably  of  20,000, 
feet.  And  yet  the  Trenton  limestone  and  Hudson  River  shales 
are  not  metamorphic.  Some  local  cases  of  alteration  occur  there, 
including  patches  of  roofing  slate;  but  the  greater  part  of  the 
shales  are  no  harder  than  the  ordinary  shales  of  the  Pennsyl- 
vania Coal  formation. 

At  a  depth  of  16,000  feet  the  temperature  of  the  earth's  crust, 
allowing  an  increase  of  1°  F.  for  60  feet  of  descent,  would  be 
about  330°  F.;  or  with  1°  F.  for  50  feet,  about  380°  F.— either 
of  which  temperatures  is  far  above  the  boiling  point  of  water; 
and  with  the  thinner  crust  of  Paleozoic  time  the  temperature 
at  this  depth  should  have  been  still  higher.  But,  notwithstand- 
ing this  heat,  and  also  the  compression  from  so  great  an  over- 
lying mass,  the  limestones  and  shales  are  not  crystalline.  The 
change  of  parts  of  the  shale  to  roofing  slate  is  no  evidence  in 
favor  of  the  efficiency  of  the  alleged  cause;  for  such  a  cause 
should  act  uniformly  over  great  areas." 

The  next  contribution  to  the  theory  of  orogeny  was  a 
series  of  papers  published  in  1873  by  Dana,  entitled  **0n 
some  results  of  the  earth's  contraction  from  cooling, 
including  a  discussion  on  the  origin  of  mountains  and 
the  nature  of  the  earth's  interior. ''^^  This  contribution, 
viewed  as  a  whole,  ranks  among  the  first  half  dozen 
papers  on  the  science  of  mountains.  The  following 
quoted  paragraphs  give  a  view  of  the  scope  of  this 
article : 

^' Kinds  and  Structure  of  Mountains,^^ 

**  While  mountains  and  mountain  chains  all  over  the  world, 
and  low  lands,  also,  have  undergone  uplifts,  in  the  course  of 
their  long  history,  that  are  not  explained  on  the  idea  that  all 


180  A  CENTURY  OF  SCIENCE 

mountain  elevating  is  simply  what  may  come  from  plication 
or  crushing,  the  component  parts  of  mountain  chains,  or  those 
simple  mountains  or  mountain  ranges  that  are  the  product  of 
one  process  of  making — may  have  received,  at  the  time  of  their 
original  making,  no  elevation  beyond  that  resulting  from 
plication. 

This  leads  us  to  a  grand  distinction  in  orography,  hitherto 
neglected,  which  is  fundamental  and  of  the  highest  interest  in 
dynamical  geology;   a  distinction  between — 

1.  A  simple  or  individual  mountain  mass  or  range,  which  is 
the  result  of  one  process  of  making,  like  an  individual  in  any 
process  of  evolution,  and  which  may  be  distinguished  as  a  mono- 
genetic  range,  being  one  in  genesis;  and 

2.  A  composite  or  polygenetic  range  or  chain,  made  up  of 
two  or  more  monogenetic  ranges  combined. 

The  Appalachian  chain — the  mountain  region  along  the 
Atlantic  border  of  North  America — is  a  polygenetic  chain;  it 
consists,  like  the  Kocky  and  other  mountain  chains,  of  several 
monogenetic  ranges,  the  more  important  of  which  are :  1.  The 
Highland  range  (including  the  Blue  Kidge  or  parts  of  it,  and 
the  Adirondacks  also,  if  these  belong  to  the  same  process  of 
making)  pre-Silurian  in  formation;  2.  The  Green  Mountain 
range,  in  western  New  England  and  eastern  New  York,  com- 
pleted essentially  after  the  Lower  Silurian  era  or  during  its 
closing  period ;  3.  The  Alleghany  range,  extending  from  south- 
ern New  York  southwestward  to  Alabama,  and  completed 
immediately  after  the  Carboniferous  age. 

The  making  of  the  Alleghany  range  was  carried  forward  at 
first  through  a  long-continued  subsidence — a  geosynclinal  (not 
a  true  synclinal,  since  the  rocks  of  the  bending  crust  may  have 
had  in  them  many  true  or  simple  synclinals  as  well  as  anti- 
clinals),  and  a  consequent  accumulation  of  sediments,  which 
occupied  the  whole  of  Paleozoic  time;  and  it  was  completed, 
finally,  in  great  breakings,  faultings  and  foldings  or  plications 
of  the  strata,  along  with  other  results  of  disturbance. 

These  examples  exhibit  the  characteristics  of  a  large  class 
of  mountain  masses  or  ranges.  A  geosynclinal  accompanied  by 
sedimentary  depositions,  and  ending  in  a  catastrophe  of  plica- 
tions and  solidification,  are  the  essential  steps,  while  metamor- 
phism  and  igneous  ejections  are  incidental  results.  The  process 
is  one  that  produces  final  stability  in  the  mass  and  its  annexation 
generally  to  the  more  stable  part  of  the  continent,  though  not 
stable  against  future  oscillations  of  level  of  wider  range,  nor 
against  denudation. 

It  is  apparent  that  in  such  a  process  of  formation  elevation 
by  direct  uplift  of  the  underlying  crust  has  no  necessary  place. 
The  attending  plications  may  make  elevations  on  a  vast  scale 


KNOWLEDGE  OF  EARTH  STRUCTURE     181 

and  so  also  may  the  shoves  upward  along  the  lines  of  fracture, 
and  crushing  may  sometimes  add  to  the  effect;  but  elevation 
from  an  upward  movement  of  the  downward  bent  crust  is  only 
an  incidental  concomitant,  if  it  occur  at  all. 

We  perceive  thus  where  the  truth  lies  in  Professor  Le  Conte's 
important  principle.  It  should  have  in  view  alone  monogenetic 
mountains  and  these  only  at  the  time  of  their  making.  It  will 
then  read,  plication  and  shovings  along  fractures  being  made 
more  prominent  than  crushing : 

Plication,  shoving  along  fractures  and  crushing  are  the  true 
sources  of  the  elevation  that  takes  place  during  the  making  of 
geosynclinal  monogenetic  mountains. 

And  the  statement  of  Professor  Hall  may  be  made  right  if 
we  recognize  the  same  distinction,  and,  also,  reverse  the  order 
and  causal  relation  of  the  two  events,  accumulation  and  sub- 
sidence ;   and  so  make  it  read : 

Regions  of  monogenetic  mountains  were,  previous,  and  pre- 
paratory, to  the  making  of  the  mountains,  areas  each  of  a  slowly 
progressing  geosynclinal,  and,  consequently,  of  thick  accumula- 
tions of  sediments. 

The  prominence  and  importance  in  orography  of  the  moun- 
tain individualities  described  above  as  originating  through  a 
geosynclinal  make  it  desirable  that  they  should  have  a  distinc- 
tive name;  and  I  therefore  propose  to  call  a  mountain  range 
of  this  kind  a  synclinorium,  from  synclinal  and  the  Greek  6po<s, 
mountain. 

This  brings  us  to  another  important  distinction  in  orographic 
geology — that  of  a  second  kind  of  monogenetic  mountain.  The 
synclinoria  were  made  through  a  progressing  geosynclinal. 
Those  of  the  second  kind,  here  referred  to,  were  produced  hy  a 
progressing  geanticlinal.  They  are  simply  the  upward  bendings 
in  the  oscillations  of  the  earth's  crust — the  geanticlinal  waves, 
and  hardly  require  a  special  name.  Yet,  if  one  is  desired,  the 
term  anticlinorium,  the  correlate  of  synclinorium,  would  be 
appropriate.  Many  of  them  have  disappeared  in  the  course  of 
the  oscillations;  and  yet,  some  may  have  been  for  a  time — 
perhaps  millions  of  years — respectable  mountains. 

The  geosynclinal  ranges  or  synclinoria  have  experienced  in 
almost  all  cases,  since  their  completion,  true  elevation  through 
great  geanticlinal  movements,  but  movements  that  embraced  a 
wider  range  of  crust  than  that  concerned  in  the  preceding  geo- 
synclinal movements,  indeed  a  range  of  crust  that  comes  strictly 
under  the  designation  of  a  polygenetic  mass." 

^^  The  Condition  of  the  Earth^s  Interior,^ 

**The  condition  of  the  earth's  interior  is  not  among  the  geo- 
logical results  of  contraction  from  cooling.      But  these  results 


182  A  CENTURY  OF  SCIENCE 

offer  an  argument  of  great  weight  respecting  the  earth 's  interior 
condition,  and  make  it  desirable  that  the  subject  should  be  dis- 
cussed in  this  connection.  Moreover,  the  facts  throw  additional 
light  on  the  preceding  topic — the  origin  of  mountains. 

It  seems  now  to  be  demonstrated  by  astronomical  and  physical 
arguments — arguments  that  are  independent,  it  should  be  noted, 
of  direct  geological  observation — that  the  interior  of  our  globe 
is  essentially  solid.  But  the  great  oscillations  of  the  earth's 
surface,  which  have  seemed  to  demand  for  explanation  a  liquid 
interior,  still  remain  facts,  and  present  apparently  a  greater 
difficulty  than  ever  to  the  geologist.  Professor  Le  Conte  's  views, 
in  volume  iv,  were  offered  by  him  as  a  method  of  meeting  this 
difficulty;  yet,  as  he  admits  in  his  concluding  remarks,  the 
oscillations  over  the  interior  of  a  continent,  and  the  fact  of  the 
greater  movements  on  the  borders  of  the  larger  ocean,  were 
left  by  him  unexplained.  Yet  these  oscillations  are  not  more 
real  than  the  changes  of  level  or  greater  oscillations  which 
occurred  along  the  sea  border,  where  mountains  were  the  final 
result;  and  this  being  a  demonstrated  truth,  no  less  than  the 
general  solidity  of  the  earth's  interior,  the  question  comes  up, 
how  are  the  two  truths  compatible? 

The  geological  argument  on  the  subject  (the  only  one  within 
our  present  purpose)  has  often  been  presented.  But  it  derives 
new  force  and  gives  clearer  revelations  when  the  facts  are  viewed 
in  the  light  of  the  principles  that  have  been  explained  in  the 
preceding  part  of  this  memoir. 

The  Appalachian  subsidence  in  the  Alleghany  region  of  35,000 
to  40,000  feet,  going  on  through  all  the  Paleozoic  era,  was  due, 
as  has  been  shown,  to  an  actual  sinking  of  the  earth's  crust 
through  lateral  pressure,  and  not  to  local  contraction  in  the 
strata  themselves  or  the  terranes  underneath.  But  such  a  sub- 
sidence is  not  possible,  unless  seven  miles — that  is,  seven  miles 
in  maximum  depth  and  over  a  hundred  in  total  breadth — ^unless 
seven  miles  of  something  were  removed,  in  its  progress,  from 
the  region  beneath. 

If  the  matter  beneath  was  not  aerial,  then  liquid  or  viscous 
rock  was  pushed  aside.  This  being  a  fact,  it  would  follow  that 
there  existed,  underneath  a  crust  of  unascertained  thickness,  a 
sea  or  lake  of  mobile  (viscous  or  plastic)  rock,  as  large  as  the 
sinking  region;  and  also  that  this  great  viscous  sea  continued 
in  existence  through  the  whole  period  of  subsidence,  or,  in  the 
case  of  the  Alleghany  region,  through  all  Paleozoic  time — an  era 
estimated  on  a  previous  page  to  cover  at  least  thirty-five  millions 
of  years,  if  time  since  the  Silurian  age  began  embraced  fifty 
millions  of  years. 

The  facts   thus  sustain  the  statement  that  lateral   pressure 


KNOWLEDGE  OF  EARTH  STRUCTURE     183 

produced  not  only  the  subsidence  of  the  Appalachian  region 
through  the  Paleozoic,  but  also,  cotemporaneously,  and  as  its 
essential  prerequisite,  the  rising  of  a  sea-border  elevation,  or 
geanticlinal,  parallel  with  it ;  and  that  both  movements  demanded 
the  existence  beneath  of  a  great  sea  of  mobile  rock." 

The  recognition  of  regional  warping  as  a  major  factor 
in  the  larger  structure  of  mountain  systems,  and  the 
expression  of  that  factor  in  the  terms  geosyncline  and 
geanticline  forms  a  notable  advance  in  geologic  thought. 
Subsequent  folding  on  a  regional  scale  results  in  the 
development  of  synclinoria  and  anticlinoria.  Van  Hise 
has  given  these  latter  terms  wide  currency,  but  appar- 
ently inadvertently  has  used  synclinorium  in  a  different 
sense  than  that  in  which  Dana  defined  it.  Dana  gave  the 
word  to  a  mountain  range  made  by  the  mashing  and  up- 
lift of  a  geosyncline,  Van  Hise  defines  it  as  a  downf  old  of 
a  large  order  of  magnitude,  embracing  anticlines  and 
synclines  within  it;  anticlinorium  he  uses  for  a  corre- 
sponding up  fold.^^  Rice  has  called  attention  to  this 
change  of  definition,^^  but  Van  Hise's  usage  is  likely  to 
prevail,  since  they  are  needed  terms  for  the  larger  moun- 
tain structure  and  do  not  require  a  determination  of  the 
previous  limits  of  upwarp  and  downwarp, — of  original 
denudation  and  deposition.  Furthermore,  a  geosyncline 
in  mountain  folding  may  have  one  side  uplifted,  the  other 
side  depressed  and  there  are  reasons  for  regarding  the 
folds  of  Pennsylvania,  Dana's  type  synclinorium,  as 
representing  but  the  western  and  downfolded  side  of  the 
Paleozoic  geosyncline.  Under  that  view  the  folded 
Appalachians  of  Pennsylvania  constitute  a  synclinorium 
in  both  the  sense  of  Dana  and  Van  Hise. 

The  Ultimate  Cause  of  Crustal  Compression, 

The  next  important  advance  in  the  theory  of  moun- 
tains was  made  by  C.  E.  Dutton  who  in  1874  published  in 
the  Journal  (8,  113-123)  an  article  entitled  *^A  criticism 
upon  the  contractional  hypothesis."  Dutton  gives  rea- 
sons for  holding  that  the  amount  of  folding  and  shorten- 
ing exhibited  in  mountain  ranges,  especially  those  of 
Tertiary  date,  is  very  much  greater  in  magnitude  and  is 
different  in  nature  and  distribution  from  that  which 


184  A  CENTUEY  OF  SCIENCE 

would  be  given  by  the  surficial  cooling  of  the  globe.  The 
following  quotations  cover  the  principal  points  in  the 
argument : 

'*The  argument  for  the  contractional  hypothesis  presupposes 
that  the  earth-mass  may  be  considered  as  consisting  of  two  por- 
tions, a  cooled  exterior  of  undetermined  (though  probably  com- 
paratively small)  depth,  inclosing  a  hot  nucleus.  .  .  .  The 
secular  loss  of  heat,  it  is  assumed,  would  be  greater  from  the 
hot  nucleus  than  from  the  exterior,  and  the  greater  consequent 
contraction  of  the  nucleus  would  therefore  gradually  withdraw 
the  support  of  the  exterior,  which  would  collapse.  The  result- 
ing strains  upon  the  exterior  would  be  mainly  tangential. 
Owing  to  considerable  inequalities  in  the  ability  of  different  por- 
tions to  resist  the  strains  thus  developed,  the  yielding  would  take 
place  at  the  lines,  or  regions  of  least  resistance,  and  the  effects 
of  the  yielding  would  be  manifested  chiefly,  or  wholly,  at  those 
places,  in  the  form  of  mountain  chains,  or  belts  of  table-lands, 
and  in  the  disturbances  of  stratification.  The  primary  division 
of  the  surface  into  areas  of  land  and  water  are  attributed  to  the 
assumed  smaller  conductivity  of  materials  underlying  the  land, 
which  have  been  left  behind  in  the  general  convergence  of  the 
surface  toward  the  center.  Regarding  these  as  the  main  and 
underlying  premises  of  the  contractional  argument,  it  is  con- 
sidered unnecessary  to  state  the  various  subsidiary  propositions 
which  have  been  advanced  to  explain  the  determination  of  this 
action  to  particular  phenomena,  since  the  main  proposition  upon 
which  they  are  based  is  considered  untenable. 

There  can  be  no  reasonable  doubt  that  the  earth-mass  consists 
of  a  cooled  exterior  inclosing  a  hot  nucleus,  and  a  necessary 
corollary  to  this  must  be  secular  cooling,  probably  accompanied 
by  contraction  of  the  cooling  portions.  But  when  we  apply  the 
known  laws  of  thermal  physics  to  ascertain  the  rate  of  this 
cooling,  and  its  distribution  through  the  mass,  the  objectionable 
character  of  the  contractional  hypothesis  becomes  obvious. 

That  Fourier's  theorem,  under  the  general  conditions  given, 
expresses  the  normal  law  of  cooling,  is  admitted  by  all  mathe- 
maticians who  have  examined  it.  The  only  ground  of  contro- 
versy must  be  upon  the  values  to  be  assigned  to  the  constants. 
But  there  seem  to  be  no  values  consistent  with  probability  which 
can  be  of  help  to  the  contractional  hypothesis.  The  applica- 
tion of  the  theorem  shows  that  below  200  or  300  miles  the  cool- 
ing has,  up  to  the  present  time,  been  extremely  little.  .  .  . 
At  present,  however,  the  unavoidable  deduction  from  this 
theorem  is  that  the  greatest  possible  contraction  due  to  secular 
cooling  is  insufficient  in  amount  to  account  for  the  phenomena 
attributed  to  it  by  the  contractional  hypothesis. 


KNOWLEDGE  OF  EARTH  STRUCTURE     185 

The  determination  of  plications  to  particular  localities  pre- 
sents difficulties  in  the  way  of  the  contractional  hypothesis  which 
have  been  underrated.  It  has  been  assumed  that  if  a  contraction 
of  the  interior  were  to  occur,  the  yielding  of  the  outer  crust 
would  take  place  at  localities  of  least  resistance.  But  this  could 
be  true  only  on  the  assumption  that  the  crust  could  have  a  hori- 
zontal movement  in  which  the  nucleus  does  not  necessarily  share. 
A  vertical  section  through  the  Appalachian  region  and  west- 
ward to  the  100th  meridian  shows  a  surface  highly  disturbed 
for  about  two  hundred  and  fifty  miles,  and  comparatively  undis- 
turbed for  more  than  a  thousand.  No  one  would  seriously  argue 
that  the  contraction  of  the  nucleus  had  been  confined  to  portions 
underlying  the  disturbed  regions:  yet  if  the  contraction  was 
general,  there  must  have  been  a  large  amount  of  slip  of  some 
portion  of  the  undisturbed  segment  over  the  nucleus.  Such  a 
proposition  would  be  very  difficult  to  defend,  even  if  the  pre- 
mises were  granted.  It  seems  as  if  the  friction  and  adhesion  of 
the  crust  upon  the  nucleus  had  been  overlooked.  Nor  could  this 
be  small,  even  though  the  crust  rested  upon  liquid  lava.  The 
attempts  which  some  eminent  geologists  have  recently  made  to 
explain  surface  corrugation  by  this  method  clearly  show  a  neg- 
lect on  their  part  to  analyze  carefully  the  system  of  forces  which 
a  contraction  of  the  nucleus  would  generate  in  the  crust.  Their 
discussions  have  been  argumentative  and  not  analytical.  The 
latter  method  of  examination  would  have  shown  them  certain 
difficulties  irreconcilable  with  their  knowledge  of  facts.  Adopt- 
ing the  argumentative  mode,  and  in  conformity  with  their  view 
regarding  the  exterior  as  a  shell  of  insufficient  coherence  to 
sustain  itself  when  its  support  is  sensibly  diminished,  the  ten- 
dency of  corrugation  to  occur  mainly  along  certain  belts,  with 
series  of  parallel  folds,  is  not  explained  by  assuming  that  these 
localities  are  regions  of  weakness.  For  a  shrinkage  of  the 
nucleus  would  throw  each  elementary  portion  of  the  crust  into 
a  state  of  strain  by  the  action  of  forces  in  all  directions  within 
its  own  tangent  plane.  A  relief  by  a  horizontal  yielding  in  one 
direction  would  by  no  means  be  a  general  relief. '* 

Dutton's  criticisms  robbed  the  current  hypothesis  of 
mountain-making  of  its  conventional  basis  without  pro- 
viding a  new  foundation.  It  was  a  quarter  of  a  cen- 
tury in  advance  of  its  time,  has  been  seldom  cited,  and 
seems  to  have  had  but  little  direct  influence  in  shaping 
subsequent  thought.  It,  however,  gave  direction  to  But- 
ton's views,  and  his  later  papers  were  far-reaching  in 
their  influence. 

If  contraction  from  external  cooling  is  not  the  cause 


186  A  CENTUEY  OF  SCIENCE 

of  the  compressive  forces  it  is  necessary  to  seek  another 
cause.  Two  years  later,  in  1876,  Dutton  attempted  to 
provide  an  answer  to  this  open  question.^*  A  review  of 
this  paper,  evidently  by  J.  D.  Dana,  is  given  in  the  Jour- 
nal. The  following  explanations  of  Button's  theory  and 
of  Dana's  comments  upon  it  are  contained  in  a  few  para- 
graphs from  this  review  (12, 142,  1876). 

* '  Captain  Dutton  presents  in  this  paper  the  views  brought  out 
in  his  article  in  volume  viii  of  this  Journal,  with  fuller  illustra- 
tions, and  adds  explanations  of  his  theory  of  the  origin  of  moun- 
tains. The  discussion  should  be  read  by  all  desiring  to  reach 
right  conclusions,  it  presenting  many  arguments  from  physical 
considerations  against  the  contraction-theory,  or  that  of  the 
uplifting  and  folding  of  strata  through  lateral  pressure.  There 
is  much  to  be  learned  before  any  theory  of  mountain-making 
shall  have  a  sufficient  foundation  in  observed  facts  to  demand 
full  confidence,  and  Captain  Dutton  merits  the  thanks  of  geolo- 
gists for  the  aid  he  has  given  them  toward  reaching  right  con- 
clusions. His  discussions  are  not  free  from  misunderstandings 
of  geological  facts,  and  if  they  fail  to  be  finally  received  it  will 
be  for  this  reason. 

We  here  give  in  a  brief  form,  and  nearly  in  his  own  words, 
the  principal  points  in  his  theory  of  mountain-making  as 
explained  in  the  later  part  of  his  memoir. 

Accepting  the  proposition  that  there  is  a  plastic  condition  of 
rock  beneath  the  earth's  crust  and  that  metamorphism  is  a 
'hydrothermal  process,'  and  believing  that  Hhe  penetration  of 
water  to  profound  depths  [in  the  earth's  crust]  is  a  well  sus- 
tained theory,'  he  says  that  great  pressure  and  a  temperature 
approaching  redness  are  essential  conditions  of  metamorphism. 
...  *  The  heaviest  portion  would  sink  into  the  lighter  colloid 
mass  underneath,  protruding  it  laterally  beneath  the  lighter 
portions  where,  by  its  lighter  density,  it  tends  to  accumulate.' 
He  adds :  '  The  resulting  movements  would  be  determined,  first, 
by  the  amount  of  difference  in  the  densities  of  the  upper  and 
lower  masses,  and,  second,  by  inequalities  in  the  thickness  of 
the  strata:  the  forces  now  become  adequate  to  the  building  of 
mountains  and  the  plication  of  strata,  and  their  modes  of  opera- 
tion agree  with  the  classes  of  facts  already  set  forth  as  the 
concomitants  of  those  features.' 

The  views  are  next  applied  to  a  system  of  plications.  *  It  has 
been  indicated  that  plications  occur  where  strata  have  rapidly 
accumulated  in  great  volume  and  in  elongated  narrow  belts; 
that  the  axes  of  plications  are  parallel  to  the  axes  of  maximum 
deposit;    and  that  the  movements   immediately   followed   the 


KNOWLEDGE  OF  EARTH  STRUCTURE     187 

deposition' — the  case  of  the  Appalachians  being  an  example  in 
which  the  accumulations  averaged  40,000  feet.  He  observes: 
'Wlierever  the  load  of  sediments  becomes  heaviest,  there  they 
sink  deepest,  protruding  the  colloid  magma  beneath  them  to  the 
adjoining  areas,  which  are  less  heavily  weighted,  forming  at 
once  both  synclinals  and  anticlinals. ' 

With  regard  to  this  new  theory,  we  might  reasonably  question 
the  existence  of  the  colloid  magma — a  condition  fundamental  to 
the  theory — and  his  evidence  that  water  penetrates  to  profound 
depths  in  the  earth's  crust  sufficient  to  make  hydrous  rocks. 
We  might  ask  for  evidence  that  the  rocks  beneath  the  Cretaceous 
and  Tertiary,  and  other  underlying  strata  of  the  Uintahs,  were 
in  such  a  colloid  state,  and  this  so  near  the  surface,  that  the 
'beds  subsided  by  their  gross  weight  as  rapidly  as  they  grew.' 

Again,  he  says  that  the  movements  of  mountain-making 
'immediately  followed  the  deposition.'  'Immediately'  sounds 
quick  to  one  who  appreciates  the  slowness  of  geological  changes. 
The  Carboniferous  age  was  very  long;  and  somewhere  in  that 
part  of  geological  time,  either  before  the  age  had  fully  ended, 
or  some  time  after  its  close,  the  epoch  of  catastrophe  began.'* 

We  see  foreshadowed  in  this  paper  the  theory  of 
isostasy,  or  condition  of  vertical  equilibrium  in  the  crust 
which  button  published  in  1889.  This  theory  has  borne 
remarkable  fruit,  but  Dutton  attempted  to  link  to  it  the 
horizontally  compressive  forces  which  have  produced 
folding  and  overthrusting.  Willis  in  1907^^  and  Hayford 
in  1911,  overlooking  Dana's  objections,  have  attempted 
to  make  a  lateral  isostatic  undertow  the  cause  of  all  hori- 
zontal movements  in  the  crust,  adopting  the  mechanism 
of  Dutton.  The  present  writer,  although  accepting  the 
principle  of  isostasy  as  an  explanation  of  broad  vertical 
movements,  has  published  papers  which  go  to  show  the 
inadequacy  of  this  h^^othesis  of  lateral  pressure ;  inade- 
quate in  time  relation,  in  amount,  and  in  expression.^ ^ 

In  1903  it  was  determined  by  several  physicists  that 
the  materials  of  the  earth's  crust  were  radioactive  and 
must  generate  throughout  geologic  time  a  quantity  of 
heat  which  perhaps  equalled  that  lost  by  radiation  into 
space.  By  1907  this  had  become  demonstrated.  The 
remarkable  conclusion  had  been  reached  that  the  earth, 
although  losing  heat,  is  not  a  cooling  globe.  Dut- 
ton's  contentions  against  mountain  growth  through 
external  cooling  and  contraction  were  thus  unexpectedly, 


188  A  CENTURY  OF  SCIENCE 

through  a  wholly  new  branch  of  knowledge,  demonstrated 
to  be  true. 

Nevertheless,  all  students  of  orogeny  are  agreed  that 
profound  compressive  forces  have  been  the  chief  agents 
in  developing  mountain  structures.  Chamberlin  was 
the  first  to  arrive  at  the  idea  that  the  shrinkage  may 
originate  in  the  deeper  portions  of  the  earth  under  the 
urgency  of  the  enormous  pressures,  apparently  by  giving 
rise  to  slow  recombinations  of  matter  into  denser 
forms.^''^ 

The  New  Era  in  the  Interpretation  of  Mountain  Structures, 

In  the  meantime,  between  1874  and  1904,  another 
advance  in  the  knowledge  of  mountain  structures  was 
taking  place  in  Europe.  Suess  studied  the  distribution 
of  mountain  arcs  over  the  earth  and  dwelt  upon  the 
prevalence  of  overthrust  structures ;  the  backland  being 
thrust  toward  and  over  the  foreland,  the  rise  of  the 
mountain  arc  or  geanticline  depressing  the  foredeep  or 
geosjmcline.  Bertrand  and  Lugeon  from  1884  to  1900 
were  reinterpreting  the  Alpine  structures  on  this  basis. 
They  showed  that  the  whole  mountain  system  had  been 
overturned  and  overthrust  from  the  south  to  an  almost 
incredible  degree.  Enormous  denudation  had  later  dis- 
severed the  northern  outlying  portions  and  given  rise  to 
*' mountains  without  roots,'' — isolated  outliers,  consist- 
ing of  overturned  masses  of  strata  which  had  accumu- 
lated as  sediments  far  to  the  southward  in  another  por- 
tion of  the  ancient  geosyncline. 

On  a  smaller  scale  similar  phenomena  are  exhibited  in 
the  Appalachians.  Willis  showed  that  the  deep  subsi- 
dence of  the  center  of  the  geosyncline  gave  an  initial  dip 
which  determined  the  position  of  yielding  under  compres- 
sion. Laboratory  experiments  brought  out  the  weakness 
of  the  stratigraphic  structure  to  resist  horizontal  com- 
pression. The  nature  of  the  stratigraphic  series  was 
shown  to  determine  whether  the  yielding  would  be  by 
mashing,  competent  folding,  or  breakage  and  overthrust. 
The  problem  of  mountain  structures  was  thus  brought 
into  the  realm  of  mechanics.  These  results  were  pub- 
lished in  three  sources  in  1893, — the  Transactions  of  the 


KNOWLEDGE  OF  EARTH  STRUCTURE     189 

American  Institute  of  Mining  Engineers,  the  thirteenth 
annual  report  of  the  United  States  Geological  Survey, 
and  the  Journal  (46,  257,  1893). 

Finally  should  be  noted  the  contributions  of  the  Lake 
Superior  school  of  geology,  in  which  the  work  of  Van 
Hise  stands  preeminent.  Under  the  economic  stimulus 
given  by  the  discovery  and  development  of  enormously 
rich  bodies  of  iron  ore,  hidden  under  Pleistocene  drift 
and  involved  in  the  complex  structures  of  vanished  moun- 
tain systems  of  ancient  date,  structural  geology  and  met- 
amorphism  have  become  exact  sciences  to  be  drawn  upon 
in  the  search  for  mineral  wealth  and  yielding  also  rich 
returns  in  a  fuller  knowledge  of  early  periods  of  earth 
history. 

Crust  Movements  as  Revealed  hy  Physiography, 

During  the  last  quarter  of  the  nineteenth  century 
another  division  of  geology,  dominantly  American,  was 
taking  form  and  growth, — the  science  of  land  forms, — 
physiography.  The  history  of  that  development  is 
treated  by  Gregory  in  the  preceding  chapter  but  some  of 
its  bearings  upon  theory,  in  so  far  as  they  affect  the  sub- 
ject of  mountain  origin,  are  necessarily  given  here. 

Powell,  Dutton,  and  Gilbert  in  their  explorations  of  the 
West  saw  the  stupendous  work  of  denudation  which  had 
been  carried  to  completion  again  and  again  during  the 
progress  of  geologic  time.  The  mountain  relief  conse- 
quently may  be  much  younger  than  the  folding  of  the 
rocks,  and  may  be  largely  or  even  wholly  due  to  recurrent 
plateau  movement,  a  doctrine  to  which  Dana  had  pre- 
viously arrived.  But  the  introduction  of  the  idea  of  the 
peneplain  opened  up  a  new  field  for  exploration  in  the 
nature  and  date  of  crust  movements.  Davis  by  this  means 
began  to  study  the  later  chapters  of  Appalachian  history, 
the  most  important  early  paper  being  published  in  1891.*^ 
Since  then  Davis,  Willis,  and  many  others  have  found 
that,  girdling  the  world,  a  large  part  of  the  mountainous 
relief  is  due  to  vertical  elevatory  forces  acting  over 
regions  of  previous  folding  and  overthrust.  In  addition, 
great  plateau  areas  of  unfolded  rocks  have  been  bodily 
lifted  one  to  two  miles,  or  more,  above  their  earlier  levels. 

12 


190  A  CENTURY  OF  SCIENCE 

They  may  be  broad  geanticlinal  arches  or  bounded  by  the 
walls  of  profound  fractures. 

The  linear  mountain  systems  made  from  deep  troughs 
of  sediments  have  come  then  to  be  recognized  as  but  one 
of  several  classes  of  mountains.  This  class,  from  its 
clear  development  in  the  Appalachians,  and  the  fact  that 
many  of  the  laws  of  mountain  structure  pertaining  to  it 
were  first  worked  out  there,  has  been  called  by  Powell  the 
Appalachian  type  (12,  414,  1876).  A  classification  of 
mountain  systems  was  proposed  by  him  in  which  moun- 
tains are  classified  into  two  major  divisions,  those  com- 
posed of  sedimentary  strata  altered  or  unaltered,  and 
those  composed  in  whole  or  in  part  of  extravasated  mate- 
rial. The  first  class  he  subdivides  into  six  sub-classes 
of  which  the  folded  Appalachians  illustrate  one.  It 
appears  to  the  writer  that  PowelPs  classification  gives 
disproportionate  importance  to  certain  types  which  he 
described;  but  nevertheless,  the  fact  that  such  a  classi- 
fication was  made,  indicates  the  growth  of  a  more  com- 
prehensive knowledge  of  mountains, — their  origin,  struc- 
ture, and  history. 

Melations  of  Crust  Movements  to  Density  and  Equilibrium, 

A  recent  important  development  in  the  fields  of  geo- 
physics and  major  crust  movements  consists  in  the  incor- 
poration into  geology  of  the  doctrine  of  isostasy.  The 
evidence  was  developed  in  the  middle  of  the  nineteenth 
century  by  the  geodetic  survey  of  India  which  indicated 
that  the  Himalayas  did  not  exert  the  gravitative  influence 
that  their  volume  called  for.  It  was  clear  that  the  crust 
beneath  that  mountain  system  was  less  dense  than 
beneath  the  plains  of  India  and  still  less  dense  than  the 
crust  beneath  the  Indian  Ocean.  This  relation  between 
density  and  elevation  indicated  some  approach  to  flota- 
tional  equilibrium  in  the  crust,  comparable  in  its  nature 
though  not  in  delicacy  of  adjustment  to  the  elevation  of 
the  surface  of  an  iceberg  above  the  ocean  level  owing  to 
its  depth  and  its  density,  less  than  that  of  the  surround- 
ing medium.  This  important  geological  conception  was 
kept  within  the  confines  of  astronomy  and  geodesy,  how- 
ever, until  Dutton  in  1876,  but  especially  in  1889,  brought 


KNOWLEDGE  OF  EARTH  STRUCTURE     191 

it  into. the  geologic  field.  A  test  of  isostasy  was  made  for 
the  United  States  by  Putnam  and  Gilbert  in  1895  and 
much  more  elaborate  investigations  have  since  been  made 
by  Hayford  and  Bowie.  These  investigations  demon- 
strate the  importance  and  reality  of  broad  warping 
forces  acting  vertically  and  related  to  the  regional  varia- 
tions of  density  in  the  crust. 

There  are  consequently  two  major  and  unrelated 
classes  of  forces  involved  in  the  making  of  mountain 
structures,  —  the  irresistible  horizontal  compressive 
forces,  arising  apparently  from  condensation  deep  within 
the  earth,  and  vertical  forces  originating  in  the  outer 
envelopes  and  tending  toward  a  hydrostatic  equilibrium. 
In  this  latter  field  of  investigation,  America,  since  the 
initial  paper  by  Dutton,  has  taken  the  lead. 

Conclusion  on  Contributions  of  America  to  Theories  of 

Orogeny, 

The  sciences  atose  in  Europe,  but  those  which  treated 
of  the  earth  were  still  in  their  infancy  when  transplanted 
to  America.  The  first  comprehensive  ideas  on  the  nature 
of  mountain  structures  arose  in  Great  Britain  and 
France.  These  ideas  served  as  a  guide  and  stimulus  to 
observation  in  the  recognition  of  deformations  in  the 
strata  of  the  Appalachian  system.  Since  1840,  however, 
America  has  ceased  to  be  a  pupil  in  this  field  of  research 
but  has  joined  as  an  equal  with  the  two  older  countries. 
New  ideas  have  been  contributed,  new  and  striking  illus- 
trations cited,  first  by  the  scientists  of  one  nation,  next  by 
those  of  another.  The  composite  mass  of  knowledge  has 
grown  as  a  common  possession.  Nevertheless,  a  review 
of  the  progress  since  1840  as  measured  by  the  contribu- 
tion of  new  ideas  shows  on  the  whole  America  at  least 
equal  to  its  intellectual  rivals,  and  at  certain  times 
actually  the  leader.  This  is  true  of  the  science  of  geol- 
ogy as  a  whole  and  also  of  the  subdivision  of  orogeny. 

Thus  far  no  mention  has  been  made  of  German  geolo- 
gists, with  the  exception  of  Suess,  an  Austrian.  German 
geology  is  voluminous  and  the  names  of  many  well-known 
geologists  could  be  cited.  But  this  article  has  sought 
to  trace  the  origin  and  growth  of  fundamental  ideas. 


192  A  CENTURY  OF  SCIENCE 

The  Germans  have  been  assiduous  observers  of  detail; 
preeminent  as  systematizers  and  classifiers,  seldom  orig- 
inators. Even  petrology,  which  might  be  regarded  as 
their  especial  field,  was  transplanted  from  Great  Britain. 
In  the  science  of  mountains  they  have  followed  in  their 
fundamental  ideas  especially  the  French. 

Turning  to  the  mediums  of  publication  through  which 
this  progress  of  knowledge  in  earth  structures  has  been 
recorded,  the  American  Journal  of  Science  stands  fore- 
most as  the  only  continuous  record  for  the  whole  century 
in  American  literature,  fulfilling  for  this  country  what  the 
Quarterly  Journal  of  the  Geological  Society  has  done  for 
Great  Britain  since  1845,  and  the  Bulletin  de  la  Societe 
Geologique  for  France  since  1830. 

Notes, 

^  H.  D.  Rogers,  Geology  of  New  Jersey,  Final  Report,  p.  115,  1840. 

« H.  D.  Rogers,  Geology  of  Pennsylvania,  vol.  2,  pt.  II,  pp.  761,  762,  1858. 

"Connecticut  Academy  of  Arts  and  Sciences,  1810;  quoted  by  G.  P. 
Merrill  in  Contributions  to  the  History  of  North  American  geology,  Ann. 
Rpt.  Smithsonian  Institution  for  1904,  p.  216. 

*  A  Sketch  of  the  geology,  mineralogy,  and  scenery  of  the  regions  con- 
tiguous to  the  river  Connecticut;  with  a  geological  map  and  drawings  of 
organic  remains;  and  occasional  botanical  notices,  the  Journal,  6,  1-86, 
201-236,  1823;    7,  1-30,  1824. 

'Clarence  King,  U.  S.  Geol.  Exploration  of  the  Fortieth  Parallel,  vol. 
1,  pp.  16,  44-48,  1878. 

•Illustrations  of  the  Huttonian  Theory  of  the  Earth,  pp.  219-238,  1802. 

'Robert  Jameson,  Elements  of  Geogno'sy,  pp.  55-57,  1808. 

•G.  P.  Merrill,  Contributions  to  the  History  of  American  Geology. 
Report  of  the  U.  S.  National  Museum  for  1904,  p.  328. 

"  H.  D.  Rogers,  Geology  of  Pennsylvania,  vol.  2,  p.  916,  1858. 

^°  James  Hall,  Natural  History  of  New  York,  Paleontology,  vol.  3,  pp. 
51-73,  1859. 

"The  Journal,  5,  423-443,  474,  475;  6,  6-14,  104-115,  161-172,  304,  381, 
382,  1873. 

"  C.  R.  Van  Hise,  Principles  of  North  American  Pre-Cambrian  Geology, 
U.  S.  Geol.  Surv.,  16th  Ann.  Report,  pt.  I,  pp.  607-612,  1896. 

^'W.  N.  Rice,  On  the  use  of  the  words  synclinorium  and  anticlinorium. 
Science,  23,  286,  287,  1906. 

"  C.  E.  Button,  Critical  observations  on  theories  of  the  earth's  physical 
evolution.  The  Penn  Monthly,  May  and  June,  1876. 

"  B.  Willis,  Research  in  China,  vol.  2,  1907. 

"Joseph  Barren,  Science,  39,  259,  260,  1909;  Jour.  Geol.,  22,  672-683, 
1914. 

"  T.  C.  Chamberlin,  Geology,  vol.  1,  pp.  541,  542,  1904. 

^*  W.  M.  Davis,  The  geological  dates  of  origin  of  certain  topographic 
forms  on  the  Atlantic  slope  of  the  United  States,  Geol.  Soe.  Am.  Bull.,  2, 
541-542,  545-586,  1891. 


A  CENTURY  OF  GOVERNMENT  GEOLOGICAIi 

SURVEYS 

By  GEORGE  OTIS  SMITH 

Director  of  the  United  States  Geological  Survey 

EVEN  a  Federal  Bureau  must  be  considered  a 
product  of  evolution :  the  past  of  the  United  States 
Geological  Survey  far  antedates  March  3,  1879. 
The  scope  of  endeavor,  the  refinement  of  method,  and 
especially  the  personnel  of  the  newly  created  service  of 
that  day  were  largely  inherited  from  pioneer  organiza- 
tions. Therefore  a  review  of  the  country's  record  of 
surveys  under  Government  auspices  becomes  more  than 
a  grateful  acknowledgment  by  the  present  generation  of 
geologists  of  the  credit  due  to  those  who  blazed  the  way ; 
it  shows  the  sequence  and  progress  in  the  contributions 
made  by  geologic  science  to  industry. 

The  earlier  stages  in  industrial  evolution  mentioned  by 
Hess^ — exploitation,  development,  and  maturity — deter- 
mine a  somewhat  similar  progressive  development  in 
geologic  investigation,  so  that  geographic  exploration 
and  geologic  reconnaissance  of  the  broadest  type  are  the 
normal  contribution  of  exact  science  whenever  and 
wherever  a  nation  is  in  the  state  of  exploitation  and 
iilitial  development  of  its  mineral  and  agricultural 
resources.  The  refinements  of  detailed  surveys  and 
quantitative  examinations  belong  rather  to  the  next  stage 
of  intensive  utilization,  or,  indeed,  they  are  the  essentials 
preliminary  to  full  use.  Thus  regrets  that  the  results  of 
present-day  work  were  not  available  fifty  years  ago  are 
largely  vain :  the  fathers  may  not  have  been  without  the 
vision ;  they  simply  did  the  work  as  their  day  and  gener- 
ation needed  it  done. 


194  A  CENTURY  OF  SCIENCE 

Twenty  years  ago  S.  F.  Emmons,  in  a  presidential 
address  before  the  Geological  Society  of  "Washington, 
divided  the  history  of  Governmental  surveys  in  this 
country  into  two  periods,  separated  in  a  general  way  by 
the  Civil  War.  The  first  of  these  was  the  period  of  geo- 
graphic exploration,  the  second  that  of  geologic  explora- 
tion. Mr.  Emmons  of  course  regarded  this  subdivision 
as  not  hard  and  fast,  yet  his  dividing  line  seems  logical, 
for  not  only  did  the  military  activities  in  the  East  neces- 
sarily suspend  exploration  in  the  West,  but  after  the  war 
national,  political,  and  economic  considerations  led  nat- 
urally to  the  demand  for  a  more  exact  knowledge  of  the 
vast  national  domain  in  the  "West.  Geography  and  geol- 
ogy are  so  closely  related  that  Mr.  Emmons 's  distinction 
of  the  two  periods  is  useful  only  with  the  limitations 
inferentially  set  by  himself — namely,  that  while  geologic 
investigation  entered  into  most  of  the  explorations  of  the 
earlier  period,  the  geologist  was  regarded  as  only  an 
accessory  in  these  exploring  expeditions;  on  the  other 
hand,  in  the  later  surveys  the  topographic  work  was 
developed  because  it  was  essential  to  the  geologic 
investigations. 

The  year  1818  was  a  notable  one  in  American  geology, 
first  of  all  in  the  appearance  of  the  American  Journal  of 
Science,  itself  so  perfect  a  vehicle  for  geological  thought 
that,  as  is  so  well  stated  by  Dr.  G.  P.  Merrill,  **a  perusal 
of  the  numbers  from  the  date  of  issue  down  to  the  present 
time  will  alone  afford  a  fair  idea  of  the  gradual  progress 
of  American  geology."  The  beginning  of  publications 
on  New  England  geology  appeared  that  year  in  Edward 
Hitchcock's  first  paper  on  the  Connecticut  Valley  (1, 105, 
1818)  and  the  Danas'  (S.  L.  and  J.  F.)  detailed  geologic 
and  mineralogic  description  of  Boston  and  vicinity ;  and 
the  ** Index''  of  Amos  Eaton  (noticed  in  this  Journal,  1, 
69)  was  the  first  of  that  long  list  of  notable  contributions 
to  American  stratigraphy  that  are  to  be  credited  to  the 
New  York  geologists. 

In  the  present  discussion,  too,  the  year  1918  can  be 
regarded  as  in  a  way  the  centennial  of  Government  geo- 
logic surveys,  for  it  was  in  1818  that  Henry  R.  School- 
craft began  his  trip  to  the  Mississippi  Valley — perhaps 
the  first  geologic  reconnaissance  into  the  West — and  it 


GOVERNMENT  GEOLOGICAL  SUEYEYS     195 

was  his  work  in  the  lead  region  which  served  to  make  him 
a  member  of  the  Cass  expedition  sent  out  by  the  Secre- 
tary of  War  in  1820  to  examine  the  metallic  wealth  of  the 
Lake  Superior  region.  The  earlier  Government  explora- 
tions of  Lewis  and  Clark,  in  1803-7,  and  of  Pike,  in  1805-7, 
were  so  exclusively  geographic  that  geologic  work  under 
Federal  auspices  must  be  regarded  as  beginning  with 
Schoolcraft  and  with  Edwin  James,  the  geologist  of  the 
expedition  of  Major  Long  in  1819-20  to  the  Rocky  Moun- 
tains. Both  these  observers  published  reports  that  are 
valuable  as  contributions  to  the  knowledge  of  little- 
known  regions. 

Any  description  of  geologic  work  under  the  Federal 
Government  that  included  no  reference  to  the  State 
surveys  would  be  inadequate,  for  in  both  date  of 
execution  and  stage  of  development  the  work  of  the  State 
geologists  must  be  given  precedence.  In  MerrilPs  Con- 
tributions to  the  History  of  American  Geology,^  whose 
modest  title  fails  even  to  suggest  that  this  work  not  only 
furnishes  the  most  useful  chronologic  record  of  the 
progress  of  the  science  on  the  American  continent  but  is 
in  fact  a  very  thesaurus  of  incidents  touching  the  per- 
sonal side  of  geology,  the  author  by  his  division  of  his 
subject  shows  that  four  decades  of  the  era  of  State  sur- 
veys elapsed  before  the  era  of  national  surveys  began. 

Thus  the  geologic  surveys  of  some  of  the  Eastern 
States  antedate  by  several  decades  any  Federal  organ- 
ization of  comparable  geologic  scope,  and  in  investiga- 
tions directed  to  local  utilitarian  problems  these  pioneer 
geologists  working  in  the  older  settled  States  of  the 
East  were  in  fact  already  conducting  work  as  detailed  in 
type  as  much  of  that  attempted  by  the  Federal  geologists 
of  the  later  period.  Even  to-day  it  is  true  in  a  general 
way  that  the  State  geologist  can  and  should  attack  many 
of  his  local  problems  with  intensive  methods  and  with 
detail  of  results  that  are  neither  practicable  nor  desirable 
for  the  larger  interstate  investigations  or  for  examina- 
tions in  newer  territory.  All  this  relation  of  State  and 
Federal  work  must  be  looked  upon  as  normal  evolution- 
ary development  of  geologic  science  in  America. 

One  who  reads  the  names  of  the  Federal  geologists  of 
the  early  days,  beginning  with  Jackson  and  Owen  and 


196  A  CENTURY  OF  SCIENCE 

following  with  such  leaders  in  Federal  work  as  Gilbert, 
Chamberlin,  King,  R.  D.  Irving,  Pumpelly,  Van  Hise, 
and  Walcott,  may  note  that  these  were  all  connected  in 
their  earlier  work  with  State  surveys.  Nor  has  the  rela- 
tion been  one-sided,  for  among  the  State  geologists 
Whitney,  Blake,  Mather,  Newberry,  J.  G.  Norwood,  Pur- 
due, Bain,  Gregory,  Ashley,  Kirk,  W.  H.  Emmons, 
DeWolf,  Mathews,  Brown,  Landes,  Moore,  and  Crider 
received  their  field  training  in  part  or  wholly  as  members 
of  a  Federal  Survey.  Moreover,  under  the  present  plan 
of  effective  cooperation  of  several  of  the  State  surveys 
with  the  United  States  Geological  Survey,  it  is  often  dif- 
ficult to  differentiate  between  the  two  in  either  personnel 
or  results,  for  it  even  happens  that  the  publishing  organ- 
ization may  not  have  been  the  major  contributor.  The 
full  record  of  American  geology,  past  and  present,  can 
not  be  set  forth  in  terms  of  Federal  auspices  alone. 

The  three  decades  preceding  the  Civil  "War,  then,  con- 
stitute the  era  of  State  surveys,  well  described  by  Mer- 
rill as  at  first  characterized  by  a  contagious  enthusiasm 
for  beginning  geologic  work,  later  by  a  more  normal 
condition  in  which  every  available  geologist  seems  to 
have  been  quietly  at  work,  and  finally  by  renewed  activity 
in  creating  new  organizations.  The  net  result  was  that 
Louisiana  and  Oregon  seem  to  have  been  the  only  States 
not  having  at  least  one  geological  survey. 

The  first  specific  appropriation  by  the  Federal  Govern- 
ment for  geologic  investigation  appears  to  have  been 
made  in  1834,  when  a  supplemental  appropriation  for 
surveys  of  roads  and  canals  under  the  War  Department, 
authorized  in  1824,  contained  the  item  ^*of  which  sum 
five  thousand  dollars  shall  be  appropriated  and  applied 
to  geological  and  mineralogical  survey  and  researches/' 
In  July,  1834,  Mr.  G.  W.  Featherstonhaugh  was  appointed 
United  States  geologist  and  employed  under  Colonel 
Abert,  U.  S.  Topographical  Engineers,  to  **  personally 
inspect  the  mineral  and  geological  character''  of  the  pub- 
lic lands  of  the  Ozark  Mountain  region.  Overlooking 
the  incidental  fact  that  this  Englishman — a  man  of 
scientific  attainment  and  large  interest  in  public  affairs — 
was  never  naturalized,^  it  must  be  placed  to  the  credit  of 
this  first  of  United  States  geologists  that  within  seven 


From  "Contributions  to  the  History  of  American  Geology  ' 

by  George  P.  Merrills. 


GOVERNMENT  GEOLOGICAL  SURVEYS     197 

months  he  completed  his  field  work  and  returned  to 
Washington,  and  on  February  17,  1835,  his  report  was 
transmitted  to  Congress.  Two  years  earlier  Feather- 
stonhaugh  had  memorialized  Congress  for  aid  in  the 
preparation  of  a  geologic  map  of  the  whole  territory  of 
the  United  States,  and  in  connection  with  this  project  he 
suggested  that  geology  as  an  aid  to  military  engineering 
should  have  a  place  in  the  curriculum  at  West  Point. 
This  first  United  States  geologist  also  appears  to  have 
combined  an  appreciation  of  the  practical  worth  of  **the 
mineral  riches  of  our  country,  their  quality,  quantity, 
and  the  facility  of  procuring  them,'^  with  an  interest  in 
the  more  scientific  side  of  geology,  though  his  hypotheses 
regarding  both  economic  geology  and  stratigraphic  and 
structural  geology  have  not  won  the  endorsement  of  all 
later  workers  in  the  same  regions.  In  all  these  respects, 
however,  Featherstonhaugh  may  stand  as  a  fairly  good 
prototype.  His  contributions  to  international  affairs 
subsequent  to  his  scientific  service  to  the  United  States 
are  of  interest;  he  served  as  one  of  Her  Majesty's  com- 
missioners in  the  settlement  of  the  Canadian-United 
States  boundary  question  in  1839-40  and  made  an  exam- 
ination of  the  disputed  area,  and  after  the  settlement  of 
this  controversy  he  was  appointed  British  Consul  for  the 
Department  of  the  Seine,  France,  where  in  1848  he  per- 
sonally engineered  the  escape  of  Louis  Philippe  from 
Havre. 

The  Federal  geologic  work  thus  started  was  soon  con- 
tinued in  surveys  of  wider  scope  and  more  thorough 
accomplishment.  The  position  of  the  Government  as  the 
proprietor  of  mineral  lands  in  the  Upper  Mississippi 
Valley  led  to  their  examination.  These  Government 
lands  containing  lead  had  been  reserved  from  sale  for 
lease  since  1807,  although  no  leases  were  issued  until  1822. 
The  amount  of  illegal  entry  and  consequent  refusal  of 
smelters  and  miners  to  pay  royalty  after  1834  forced  the 
issue  upon  the  attention  of  Congress,  and  in  1839  Presi- 
dent Van  Buren  was  requested  to  present  to  Congress  a 
plan  for  the  sale  of  the  public  mineral  lands.  In  carrying 
out  this  policy  Dr.  David  Dale  Owen  was  selected  to 
make  the  necessary  survey. 

Owen  had  served  as  an  assistant  on  the  State  Survey 


198  A  CENTURY  OF  SCIENCE 

of  Tennessee  and  as  the  first  State  geologist  of  Indiana, 
and  he  organized  the  new  work  promptly  and  effectively. 
Although  suffering  from  the  handicap  unfortunately 
known  by  geologists  of  the  present  day — the  receipt  late 
in  the  season  (August  17,  1839)  of  authority  to  begin 
work — within  exactly  a  month  he  had  his  force  of  139 
assistants  organized  into  24  field  parties,  instructed  in 
'*such  elementary  principles  of  geology  as  were  neces- 
sary to  their  performance  of  the  duties  required  of 
them/'  His  plan  of  campaign  provided  for  a  northward 
drive  at  a  predetermined  rate  of  traverse  for  each  party, 
with  periodic  reports  to  himself  at  appointed  stations, 
**to  receive  which  reports  and  to  examine  the  country  in 
person''  he  crossed  the  area  under  survey  eleven  times. 
The  result  of  such  masterful  leadership  was  the  comple- 
tion of  the  exploration  of  all  the  lands  comprehended  in 
his  orders  in  two  months  and  six  days,  and  his  report  on 
this  great  area — about  11,000  square  miles — ^bears  date 
of  April  2, 1840. 

Eight  years  later  Doctor  Owen  made  a  survey  of  an 
even  larger  area,  continuing  his  examination  northward 
to  Lake  Superior.  Again  his  report  was  published 
promptly,  and  he  continued  for  several  years  his  exam- 
ination of  the  Northwest  Territory,  submitting  his  final 
report  in  1851.  It  is  interesting  to  note  that  in  his 
earlier  report  Doctor  Owen  subscribed  himself  as  ^^Prin- 
cipal Agent  to  explore  the  Mineral  Lands  of  the  United 
States,"  but  that  in  the  later  report  he  was  *^U.  S.  Geolo- 
gist for  Wisconsin. ' '  The  two  surveys  together  covered 
57,000  square  miles. 

During  the  same  period  similar  surveys  were  being 
made  in  northern  Michigan  by  Dr.  Charles  T.  Jackson, 
1847-48,  and  Foster  and  Whitney,  1849-51.  These  sur- 
veys also  had  been  hastened  by  the  *^ copper  fever"  of 
1844-46,  with  wholesale  issue  of  permits  and  leases.  Con- 
gress in  1847  authorizing  the  sale  of  the  mineral  lands 
and  a  geological  survey  of  the  Lake  Superior  district. 
The  execution  of  these  surveys  under  Jackson  and  under 
Foster  and  Whitney  and  the  prompt  publication  in  1851 
of  the  maps  of  the  whole  region  materially  helped  to 
establish  copper  mining  on  a  more  conservative  basis. 


GOVERNMENT  GEOLOGICAL  SURVEYS     199 

and  the  development  of  the  Lake  Superior  region 
was  rapid.* 

These  land-classification  surveys,  with  their  definite 
purpose,  represent  the  best  geologic  work  of  the  time. 
The  plan  necessitated  thoroughgoing  field  work  with  con- 
siderable detail  and  prompt  publication  of  systematic 
reports,  and  in  the  working  up  of  the  results  specialists 
like  James  Hall  and  Joseph  Leidy  contributed,  while 
F.  B.  Meek  was  an  assistant  of  Owen.  It  is  worthy  of 
note  that  had  not  Doctor  Houghton,  the  State  geologist  of 
Michigan,  met  an  untimely  death  in  1847,  effective  coop- 
eration of  the  State  Survey  with  the  Federal  officials 
would  have  combined  geologic  investigation  with  the 
execution  of  the  linear  surveys.^ 

Belonging  to  the  same  period  of  geologic  exploration 
was  the  service  of  J.  D.  Dana,  as  United  States  Geologist 
on  the  Wilkes  Exploring  Expedition,  the  disaster  to 
which  compelled  his  return  from  the  Pacific  Coast  over- 
land and  resulted  in  his  geologic  observations  on  Oregon 
and  northern  California. 

The  military  expeditions  during  the  decade  1850-60 
and  the  earlier  expeditions  of  Fremont  added  to  the 
geographic  knowledge  of  the  Western  country  and  also 
contributed  to  geologic  science,  largely  through  collec- 
tions of  rocks  and  fossils,  usually  reported  on  by  the 
specialists  of  the  day.  Thus  the  names  of  Hall,  Con- 
rad, Hitchcock,  and  Meek  appear  in  the  published 
reports  on  these  explorations,  while  Marcou,  Blake,- 
Newberry,  Gibbs,  Evans,  Hayden,  Parry,  Shumard, 
Schiel,  Antisell,  and  Engelmann  were  geologists  attached 
to  the  field  expeditions.  In  1852  geologic  investigation 
was  seemingly  so  popular  as  to  necessitate  the  statutory 
prohibition  *^  there  shall  be  no  further  geological  survey 
by  the  Government  unless  hereafter  authorized  by  law." 

Certain  of  these  explorations  had  a  specific  pur- 
pose: several  of  them  sought  a  practical  route  for 
a  transcontinental  railroad;  another  a  new  wagon 
road  across  Utah  and  Nevada;  and  one  under 
Colonel  Pope,  with  G.  G.  Shumard  as  geologist,  was 
sent  out  **for  boring  Artesian  Wells  along  the  line 
of    the    32d    Parallel''    in    New    Mexico.      The    pub- 


200  A  CENTURY  OF  SCIENCE 

lished  reports  varied  greatly  in  scientific  value  and  in 
carefulness  of  preparation,  while  the  publication  of  at 
least  two  reports  was  delayed  until  long  after  the  war, 
and  the  manuscript  of  another  was  lost.  The  report  of 
the  expedition  of  Major  Emory  contained  a  colored 
geologic  map  of  the  western  half  of  the  country,  a  pioneer 
publication,  for  the  map  prepared  by  Marcou  extended 
only  to  the  106th  meridian. 

Thus  in  the  first  period  of  Government  surveys,  cover- 
ing about  forty  years,  the  great  West,  with  its  wealth  of 
public  lands,  was  well  traversed  by  exploratory  surveys, 
which  furnished,  however,  only  general  outlines  for  a 
comprehension  of  the  stratigraphy  and  structure  of 
mountain  and  valley,  plain  and  plateau.  To  an  even  less 
degree  was  there  any  realization  of  the  economic  possi- 
bilities of  the  vast  territory  west  of  the  Mississippi. 
President  Jefferson,  in  planning  the  Lewis  and  Clark 
expedition,  had  stated  his  special  interest  in  the  mineral 
resources  of  the  region  to  be  traversed.  Nearly  forty 
years  later  Doctor  Owen  was  strongly  impressed  with 
the  commercial  promise  of  the  region  he  surveyed.  His 
reports  contain  analyses  of  ores  and  statistics  of  produc- 
tion; he  compared  the  lead  output  of  Wisconsin,  Iowa, 
and  Illinois  with  that  of  Europe  and  foretold  the  value 
of  the  iron,  copper,  and  zinc  deposits  of  the  area;  he 
outlined  the  extent  of  the  Illinois  coal  field ;  and  he  laid 
equal  emphasis  upon  the  agricultural  possibilities  of  the 
'region.  Indeed,  so  optimistic  were  Owen's  general  con- 
clusions that  he  referred  to  his  separate  township  plats, 
with  their  detailed  descriptions,  as  the  basis  for  his  san- 
guine opinions,  realizing  that  **the  explorer  is  apt  to 
become  the  special  pleader."  With  equal  breadth  of 
view  and  thoroughness  of  execution  the  surveys  of  Fos- 
ter and  Whitney  laid  the  foundation  for  the  development 
of  the  copper  and  iron  resources  of  the  Lake  Superior 
region,  and  although  these  areas  were  largely  wilderness 
and  not  adapted  to  rapid  traverse  or  easy  observation 
the  reports  on  their  explorations  nevertheless  compare 
most  favorably  with  the  contributions  of  geologists  work- 
ing in  the  more  hospitable  regions  in  the  older  States. 

The  period  following  the  Civil  War  naturally  became 
one  of  national  expansion,  the  faces  of  many  were  turned 


GOVERNMENT  GEOLOGICAL  SURVEYS     201 

westward,  and  exploration  of  the  national  domain  for  its 
industrial  possibilities  took  on  fresh  interest.  Home- 
seekers  and  miners  largely  made  up  this  army  of  peace- 
ful invasion,  and  the  winning  of  the  West  began  on  a 
scale  quite  different  from  that  of  the  days  of  the  military 
path-finding  expeditions  of  Fremont  and  other  Army 
officers.  Thus  the  nation  was  aroused  to  the  task  of 
investigating  its  public  lands  and  Congress  gave  the  sup- 
port needed  to  make  geologic  exploration  possible  on  a 
large  scale. 

Geologic  surveys  of  a  high  order  were  continued 
in  the  older  States,  as  shown  by  the  contributions 
during  this  period  of  J.  P.  Lesley  and  G.  H.  Cook  in 
the  East,  W.  C.  Kerr,  E.  W.  Hilgard,  and  E.  A. 
Smith  in  the  South,  and  J.  S.  Newberry,  C.  A. 
White,  Raphael  Pumpelly,  T.  C.  Chamberlin,  Alex- 
ander Winchell,  and  T.  B.  Brooks  in  the  Central  States. 
To  the  north  the  Canadian  Survey,  organized  in  1841 
under  Logan,  had  continued  under  the  same  sturdy 
leadership  until  1869,  when  the  experienced  and  talented 
Doctor  Selwyn  became  Director.  As  contrasted  with  the 
short  careers  of  most  of  the  State  Surveys  and  with  the 
temporary  character  of  all  of  the  Federal  undertakings 
in  geologic  investigation,  the  continuance  of  the  Cana- 
dian Geological  Survey  for  more  than  half  a  century 
under  two  directors  gave  opportunity  for  continuity  of 
effort  in  making  known  to  the  people  of  the  Dominion  its 
resources  and  at  the  same  time  contributing  to  the  world 
much  pure  science. 

Passing  with  simple  mention  the  two  Government  expe- 
ditions into  the  Black  Hills,  which  afforded  opportunity 
for  geologic  exploration  by  N.  H.  Winchell  in  1874  and  by 
Jenney  and  Newton  in  1875,  the  record  of  geologic  work 
under  Government  auspices  in  the  period  immediately 
following  the  Civil  War  groups  itself  around  the  names 
of  four  leaders — Hayden,  King,  Powell,  and  Wheeler. 
The  four  organizations,  distinguished  commonly  by  the 
names  of  these  four  masterful  organizers,  occupied  the 
Western  field  more  or  less  continuously  from  1867  to  1878, 
and  the  sum  total  of  their  contributions  to  geography 
and  geology  was  large  indeed.  In  the  words  of  Clarence 
King,«  '*  Eighteen  hundred  and  sixty-seven,  therefore. 


202  A  CENTURY  OF  SCIENCE 

marks,  in  the  history  of  national  geological  work,  a  turn- 
ing point,  when  the  science  ceased  to  be  dragged  in  the 
dust  of  rapid  exploration  and  took  a  commanding  posi- 
tion in  the  professional  work  of  the  country. ' '  Together 
these  four  expeditions  covered  half  a  million  square 
miles,  or  more  than  a  third  of  the  area  of  the  United 
States  west  of  the  one-hundredth  meridian,  and  the  cost 
of  all  this  work  was  approximately  two  million  dollars, 
which  was  a  small  fraction  of  its  value  to  the  nation 
counting  only  the  impetus  given  to  settlement  and  utili- 
zation. 

As  viewed  from  a  distance  of  nearly  half  a  century, 
these  four  surveys  differed  much  in  plan  of  organization, 
scope  of  purpose,  and  success  of  execution,  so  that  com- 
parison would  have  little  value  except  as  possibly  bear- 
ing upon  the  work  of  the  larger  organization  which 
followed  them  and  became  the  heir  not  only  to  much  that 
had  been  attained  by  these  pioneer  surveys  but  also  to 
the  great  task  uncompleted  by  them.  So,  if  in  the 
earliest  days  of  the  present  United  States  Geological 
Survey  there  may  have  been  a  certain  partisanship  in 
tracing  derived  characters  in  the  new  organization,  it  is 
even  now  worth  while  to  recognize  the  real  origin  of 
much  that  is  credited  to  present-day  development. 

Dr.  F.  Y.  Hayden  was  the  first  of  these  Survey  leaders 
to  engage  in  geological  exploration.  He  visited  the  Bad- 
lands as  early  as  1853,  and  his  connection  with  subse- 
quent expeditions  was  interrupted  only  by  his  service  as 
a  surgeon  in  the  Federal  Army  during  the  war.  In  1867, 
however,  Hayden  resumed  his  geologic  work  as  United 
States  Geologist  in  Nebraska,  operating  under  direction 
of  the  Commissioner  of  the  General  Land  Office.  In  the 
following  eleven  years  the  activities  of  the  Hayden  Sur- 
vey— the  *^  Geological  and  Geographical  Survey  of  the 
Territories" — extended  into  Wyoming,  Colorado,  New 
Mexico,  Montana,  and  Idaho,  covering  with  areal  sur- 
veys 107,000  square  miles.  This  Survey,  as  might  be 
expected  from  the  long  experience  of  its  leader,  made 
large  contributions  to  stratigraphy,  which  involved 
notable  paleontologic  work  by  Cope,  Meek,  and  Les- 
quereux.  Next  in  importance  was  the  structural  work  of 
A.  C.  Peale,  W.  H.  Holmes,  Capt.  C.  E.  Button,  and  Dr. 


GOVERNMENT  GEOLOGICAL  SURVEYS     203 

Hayden  himself,  and  the  influence  of  these  expeditions  in 
popularizing  geology  should  not  be  overlooked.  The 
expedition  of  1871  into  the  geyser  region  on  the  upper 
Yellowstone  resulted  in  the  creation  of  the  first  of  the 
national  parks.  W.  H.  Holmes  began  his  artistic  contri- 
butions to  geology  in  1872  with  this  Survey.  Topo- 
graphic mapping  was  added  to  the  geologic  exploration, 
James  T.  Gardner  and  A.  D.  Wilson  joining  the  Hayden 
Survey  after  earlier  service  on  the  King  Survey  and 
Henry  Gannett  being  a  member  of  parties,  first  as  astron- 
omer and  later  as  topographer  in  charge.  The  accom- 
plishment of  the  Hayden  Survey  itself  and  the  later  work 
of  many  of  its  members  show  that  this  organization  pos- 
sessed a  corps  of  strong  men. 

The  King  Survey  was  a  smaller  organization,  with 
Congressional  authorization  of  definite  scope  and  a  sys- 
tematic plan  of  operation.  The  beginning  of  construc- 
tion of  the  Union  Pacific  terminated  the  period  of  the 
railroad  surveys  under  the  War  Department  and 
afforded  opportunity  for  geologic  work  that  would  be 
more  than  exploratory:  the  opening  up  of  the  new 
country  made  investigation  of  its  resources  logical. 
This  fact  was  recognized  by  Clarence  King,  who  had 
traversed  the  same  route  as  a  member  of  an  emigrant 
train  with  his  friend  James  T.  Gardner.  His  plan  to 
make  a  geological  cross  section  of  the  Cordilleras,  with  a 
study  of  the  resources  along  the  route  of  the  Pacific  rail- 
roads, won  the  support  of  Congress,  and  the  **  Geological 
Exploration  of  the  Fortieth  Parallel' '  was  authorized  in 
1867,  with  Clarence  King  as  geologist  in  charge,  under 
the  Chief  of  Engineers  of  the  Army.  Field  work  was 
begun  in  the  summer  of  that  year,  and  it  is  interesting  to 
note  that  Mr.  King  and  his  small  force  of  geological 
assistants — the  two  Hagues  and  S.  F.  Emmons — ^began 
at  the  western  end  of  this  cross  section,  and  in  this 
and  subsequent  years  extended  the  survey  from  the  east 
front  of  the  Sierra  Nevada  to  Cheyenne,  covering  a  belt 
of  territory  about  100  miles  in  width.  This  comprehen- 
sive plan  was  carried  out  in  the  field  operations,  and  the 
scientific  and  economic  results  were  systematically 
worked  up  in  the  reports,  which  appeared  in  1870-80. 
The  only  departure  from  this  plan  was  a  study  of  the 


204  A  CENTURY  OF  SCIENCE 

volcanic  mountains  Shasta,  Rainier,  and  Hood,  in  1870, 
occasioned  by  an  unexpected  and  unsolicited  appropria- 
tion for  field  work,  and  that  summer's  work  resulted  in 
the  discovery  of  active  glaciers,  the  first  known  within 
the  United  States. 

The  Fortieth  Parallel  Survey  is  to  be  credited  with 
contributions  to  the  knowledge  of  the  stratigraphy  of  the 
West,  the  region  traversed  being  remarkably  representa- 
tive of  the  stratigraphic  column,  to  which  was  added  the 
paleontologic  work  of  Marsh,  Meek,  Hall,  and  Whitfield, 
while  the  attempt  was  made  to  interpret  the  sedimentary 
record  in  terms  of  Paleozoic,  Mesozoic,  and  Tertiary 
geography.  King's  plan  of  survey  included  large  use  of 
topographic  mapping  with  astronomic  base  and  triangu- 
lation  control  and  contours  based  upon  barometric  eleva- 
tions. The  results  were  pronounced  by  an  unfriendly 
critic*^  as  ''very  valuable,  especially  from  a  geological 
point  of  view,"  but  unfortunate  in  being  the  forerunner 
of  work  in  which  Government  geologists  ''have  presumed 
to  arrogate  the  control  of  the  fundamental  operations  of 
a  topographic  survey."  To  the  King  Survey  must  be 
credited  the  introduction  of  systematic  contour  mapping 
and  the  use  of  contour  maps  for  purposes  of  geology. 
In  two  other  respects  the  King  Survey  contributed 
largely  to  future  Government  work:  microscopical 
petrography  in  the  United  States  may  be  said  to  have 
begun  with  the  visit  of  Professor  Zirkel  to  this  country  as 
a  member  of  this  Survey  in  1875,  and  the  report  of  J.  D. 
Hague  on  "Mining  Industry"  was  the  fitting  expression 
of  the  emphasis  then  put  on  the  study  of  the  mineral 
resources  of  this  newly  opened  territory,  a  subject  of 
investigation  that  was  in  large  part  the  true  basis  of 
King's  project  rather  than  simply  "the  immediate 
excuse  for  the  Survey."  An  earlier  influence  in  the  sci- 
entific study  of  ore  deposits  had  come  from  Von  Richt- 
hofen's  investigation  of  the  Comstock  Lode  in  1865  and 
his  subsequent  work  with  Whitney  in  California.  The 
incident  of  King's  relation  to  the  diamond  fraud  in  Ari- 
zona in  1872  furnished  a  precedent  for  public  servants  of 
a  later  day ;  he  investigated  the  reported  find  from  scien- 
tific interest  but  exposed  it  with  all  the  zeal  of  a  publicist 
and  truth  lover.    In  a  word,  the  Fortieth  Parallel  Sur- 


^rvv^Jj, 


GOVERNAiENT  GEOLOGICAL  SUEVEYS     205 

vey  commands  our  admiration  for  its  brilliant  plan, 
thoroughgoing  work  in  field  and  office,  and  high  quality 
of  personnel. 

Major  J.  W.  Powell  began  his  large  contribution  to 
Government  surveys  with  his  exploration  of  the  Grand 
Canyon  in  1869,  the  Congressional  recognition  of  his 
expedition  being  limited  to  an  authorization  for  the  issue 
of  rations  by  the  War  Department.  Small  appropria- 
tions were  made  in  the  following  years,  and  in  1874  full 
authorization  was  given  for  the  continuance  of  his  survey 
in  Utah  under  the  Secretary  of  the  Interior  and  was 
followed  by  the  adoption  of  the  name  **  United  States 
Geographical  and  Geological  Survey  of  the  Rocky  Moun- 
tain Region.''  This  organization  was  the  least  preten- 
tious of  the  four  operating  during  this  period — it  covered 
less  area,  expended  less  public  money,  and  published  much 
less — but  its  contribution  to  American  geology  is  not  to  be 
measured  by  miles  or  pages  but  by  ideas.  Its  physical 
environment  favored  this  survey,  and  in  the  work  of 
Powell,  Dutton,  and  Gilbert  can  be  seen  the  beginnings  of 
physiography  on  the  heroic  scale  exemplified  in  the 
Grand  Canyon  and  the  High  Plateaus.  The  first  use  of 
terms  like  **base  level  of  erosion,"  ** consequent  and 
antecedent  drainage,''  and  ** laccolith"  marked  the  intro- 
duction of  new  ideas  in  the  interpretation  of  land  sculp- 
ture and  geologic  structure.  The  daring  boat  trip  of 
Powell  was  no  less  brilliant  than  his  simple  explanation 
of  the  Grand  Canyon  itself. 

*  *  The  United  States  Geographical  Surveys  West  of  the 
100th  Meridian"  was  the  title  given  to  the  explorations 
made  under  Lieut.  G.  M.  Wheeler,  of  the  Engineer 
Corps,  which  began  with  topographic  reconnaissances  in 
Nevada,  Utah,  and  Arizona,  specifically  authorized  by 
Congress  in  1872.  From  the  standpoint  of  American 
geology  this  could  be  better  known  as  the  Gilbert  Survey, 
Mr.  G.  K.  Gilbert  serving  for  the  three  years  1871-73,  the 
later  part  of  the  time  with  the  title  of  chief  geological 
assistant.  Gilbert's  contributions  included  his  descrip- 
tion of  Basin  Range  structure,  his  first  account  of  old 
Lake  Bonneville,  and  his  discussion  of  the  erosion  phe- 
nomena of  the  desert  country.  J.  J.  Stevenson  also 
served  later  as  a  geologist  of  this  Survey,  and  A.  R.  Mar- 
is 


206  A  CENTURY  OF  SCIENCE 

vine,  E.  E.  Howell,  E.  D.  Cope,  Jules  Marcou,  and  I.  C. 
Russell  were  connected  with  the  field  parties.  Captain 
Wheeler's  own  claim  for  the  work  of  his  Survey  empha- 
sized its  geographic  side,  for  he  regarded  the  results  as 
the  partial  completion  of  a  systematic  topographic  sur- 
vey of  the  country. 

By  1878,  when  the  Fortieth  Parallel  Survey  had  com- 
pleted the  work  planned  by  its  chief,  three  of  these  inde- 
pendent surveys  still  contended  for  Federal  support  and 
for  scientific  occupation  of  the  most  attractive  portions 
of  the  Western  country.  Unrestrained  competition  of 
this  kind,  even  in  the  public  service,  proves  as  wasteful  as 
unregulated  competition  in  private  business,^  and  Con- 
gress appealed  to  the  National  Academy  of  Sciences  for  a 
plan  for  Government  surveys  to  **  secure  the  best  results 
at  the  least  possible  cost."  Under  instructions  by  Con- 
gress the  National  Academy  considered  all  the  work 
relating  to  scientific  surveys^  and  reported  to  Congress 
a  plan  prepared  by  a  speciarcommittee,  whose  member- 
ship included  the  illustrious  names  of  Marsh,  Dana, 
Rogers,  Newberry,  Trowbridge,  Newcomb,  and  Agassiz. 
This  report,  which  was  adopted  by  the  Academy  with 
only  one  dissenting  vote,  grouped  all  surveys — geodetic, 
topographic,  land  parceling,  and  economic — ^under  two 
distinct  heads,  surveys  of  mensuration  and  surveys  of 
geology.  At  that  time  -^ve  independent  organizations  in 
three  different  departments  were  carrying  on  surveys  of 
mensuration,  and  the  Academy  recommended  that  all 
such  work  be  combined  under  the  Coast  and  Geodetic 
Survey  with  the  new  name  Coast  and  Interior  Survey. 
For  the  investigation  of  the  natural  resources  of  the  pub- 
lic domain  and  the  classification  of  the  public  lands  a 
new  organization  was  proposed,  the  United  States  Geo- 
logical Survey.  The  functions  of  these  two  surveys  and 
of  a  third  coordinate  bureau  in  the  Interior  Department, 
the  Land  Office,  were  carefully  defined  and  their  inter- 
relations fully  recognized  and  provided  for  in  the  plan 
presented  to  Congress.  Viewed  in  the  light  of  39  years 
of  experience  the  National  Academy  plan  would  be 
indorsed  by  most  of  us  as  eminently  practical,  and  the 
report  stands  as  a  splendid  example  of  public  service  ren- 
dered by  America's  leading  scientists.     The  legislation 


GOVERNMENT  GEOLOGICAL  SURVEYS     207 

wliich  embodied  the  entire  plan,  however,  failed  of  pas- 
sage in  Congress. 

The  natural  activity  behind  the  scenes  of  the  conflicting 
interests  represented  by  those  connected  with  the  sev- 
eral surveys  may  be  seen  in  the  legislative  history  of  the 
moves  leading  up  to  the  creation  of  the  United  States 
Geological  Survey.  In  the  last  session  of  the  45th  Con- 
gress the  special  legislation  embodying  the  recommenda- 
tions of  the  National  Academy  was  included  in  the 
Legislative,  Executive,  and  Judicial  Appropriation  bill 
as  it  passed  the  House  of  Representatives,  while  the  Sun- 
dry Civil  Appropriation  bill  carried  an  item  simply  mak- 
ing effective  the  longer  section  in  the  other  appropriation 
bill.  The  item  in  the  Legislative  appropriation  bill 
created  the  office  of  the  Director  of  the  Geological  Sur- 
vey, provided  his  salary,  and  defined  his  duties,  as  well 
as  specifically  terminating  the  operations  of  the  three 
older  organizations.  The  item  in  the  Sundry  Civil  bill  as 
it  passed  the  House  appropriated  $100,000  for  the  new 
Geological  Survey,  but  when  this  appropriation  bill  was 
reported  to  the  Senate  a  committee  amendment  added 
the  words  '*of  the  Territories,''  and  further  amendments 
offered  on  the  floor  changed  the  item  so  as  to  provide 
specifically  and  exclusively  for  the  continuation  of  the 
Hayden  Survey.  Other  amendments  provided  small 
appropriations  for  the  completion  of  the  reports  of  the 
Powell  and  Wheeler  surveys,  and  the  bill  passed  the  Sen- 
ate in  this  form.  The  Legislative  Appropriation  bill  was 
similarly  pruned,  while  in  the  Senate,  of  all  reference  to 
the  proposed  new  organization.  This  bill,  however,  died 
in  conference,  but  in  the  last  hours  of  the  session  the 
conferees  on  the  Sundry  Civil  bill  took  unto  themselves 
legislative  powers  and  transferred  from  the  dead  bill  to 
the  pending  measure  all  the  language  which  constitutes 
the  '* organic  act''  of  the  United  States  Geological  Sur- 
vey. This  action  was  denounced  in  the  Senate  as  **a 
wide  departure  from  the  authority  that  is  possessed  by 
a  conference  committee,"  and  it  was  further  stated  in 
debate  that  the  inserted  provision  which  created  a  new 
office  and  discontinued  the  existing  surveys  was  one 
**  which  neither  the  Committee  of  the  Senate  nor  the  Sen- 
ate itself  ever  saw."     This  assertion  was  perhaps  par- 


208  A  CENTURY  OF  SCIENCE 

liamentarily  sound  in  that  the  language  was  new  to  the 
Sundry  Civil  bill,  yet  actually  the  Senate  had  only  two 
days  before  stricken  the  same  proposed  legislation  from 
the  pending  Legislative  Appropriation  bill.  However, 
the  House  conferees — Representatives  Atkins  of  Tennes- 
see, Hewett  of  New  York,  and  Hale  of  Maine — had  real- 
ized their  tactical  advantage,  and  the  Senate,  after  a 
brief  debate,  voted  on  March  3  to  concur  in  the  report  of 
the  committee  of  conference,  thus  reversing  all  their 
earlier  action,  in  which  the  friends  of  the  Hayden  and 
Wheeler  organizations  apparently  had  commanded  more 
votes  than  the  advocates  of  the  National  Academy  plan. 

Clarence  King  was  appointed  first  Director  of  the 
United  States  Geological  Survey  on  April  3,  1879,  and 
began  the  work  of  organization.  With  his  proven  genius 
for  administration.  King  promptly  resolved  the  doubt  as 
to  the  meaning  of  the  term  ^^ national  domain*'  in  the 
language  defining  the  duties  of  the  Director  by  taking  the 
conservative  side  and  limiting  the  work  of  the  new  organ- 
ization to  the  region  west  of  the  102d  meridian.  This 
region  was  divided  into  four  geological  divisions,  and  for 
economy  of  time  and  money  field  headquarters  were 
established  for  these  divisions.  The  Division  of  the 
Rocky  Mountains  was  placed  under  Mr.  Emmons  as 
geologist  in  charge,  the  Division  of  the  Colorado  under 
Captain  Dutton,  the  Division  of  the  Great  Basin  under 
Mr.  Gilbert,  and  the  Division  of  the  Pacific  under  Arnold 
Hague.  The  Division  of  the  Colorado  was  intended  as 
merely  temporary  for  the  purpose  of  bringing  to  comple- 
tion the  scientific  work  of  the  Powell  Survey.  Similarly 
Dr.  Hayden  was  given  the  opportunity  to  prepare  a  sys- 
tematic digest  of  his  scientific  results.  This  organ- 
ization of  the  work  and  the  selection  of  geolo- 
gists in  charge  showed  the  relation  of  the  new  and  the 
old,  and  a  glance  at  the  personnel  of  the  new  Survey 
indicates  the  extent  to  which  the  geologic  investigation 
of  the  Western  country  was  to  continue  without  interrup- 
tion. Of  the  twenty-four  geologists  and  topographers 
listed  in  the  first  administrative  report,  four  had  been 
connected  with  the  Powell  Survey,  two  with  the  Hayden, 
three  with  the  Wheeler,  and  five  with  the  King  Survey. 

In  planning  the  initial  work  of  the   United   States 


tkMei/v  h. 


GOVERNMENT  GEOLOGICAL  SURVEYS    209 

Geological  Survey,  the  Director  speaks  of  the  "most 
important  geological  subjects*'  and  ** mining  industries," 
of  "instructive  geological  structure''  and  "great  bullion 
yield"  in  the  same  sentences,  so  that  the  intent  was  plain 
to  make  the  geologic  investigations  both  theoretical  and 
practical. 

It  was  expected  that  the  field  of  operations  of  this 
Federal  Survey  would  be  at  once  extended  by  Congress 
over  the  whole  United  States,  but  the  measure  making 
this  extension,  which  would  simply  carry  out  the  intent 
of  the  f ramers  of  the  legislation  creating  the  new  bureau, 
passed  the  House  alone,  and  it  was  only  by  subsequent 
modification  of  the  wording  of  appropriation  items  that 
the  United  States  Geological  Survey  became  national  in 
scope  as  well  as  in  name.  The  critical  question  of  the 
effective  coordination  of  State  and  Federal  geologic  sur- 
veys was  met  by  Director  King,  who  corrected  an  errone- 
ous impression  "industriously  circulated"  by  stating 
his  policy  to  be  to  urge  the  inauguration  and  continuance 
of  State  surveys.^  This  was  the  initial  step  in  the 
cooperation  between  State  and  Federal  surveys  which 
became  effective  on  a  large  scale  in  subsequent  years. 

Though  the  Geological  Survey  has  extended  its  opera- 
tions over  the  whole  United  States,  its  largest  activities 
have  always  been  directed  toward  the  exploration  and 
development  of  the  newer  territory  in  the  public-land 
States.  All  four  of  its  directors  had  their  field  training 
in  the  West :  the  name  of  Major  Powell,  who  succeeded 
King  in  1880,  is  inseparably  connected  with  scientific 
exploration ;  Charles  D.  Walcott,  who  was  Director  from 
1894  to  1907,  the  period  of  the  Survey's  greatest  expan- 
sion, made  the  largest  contribution  to  the  Paleozoic  stra- 
tigraphy and  paleontology  of  the  West ;  and  the  present 
Director  spent  seven  field  seasons  in  the  Northern  Cas- 
cades and  one  in  a  mining  district  in  Utah.  The  scope  of 
the  activities  both  East  and  West  as  developed  during 
the  39  years  since  the  establishment  of  the  new  bureau 
can  be  best  described,  perhaps,  in  terms  of  its  present 
functions  as  expressed  in  the  organization  of  to-day. 

The  growth  of  the  Survey  is  measured  in  the  increase 
of  annual  appropriation  from  $106,000  in  1879-80  to  the 
amount  available  for  the  current  year — $1,925,520,  not 


210  A  CENTURY  OF  SCIENCE 

including  half  a  million  dollars  from  War  Department 
appropriations  being  spent  in  the  topographic  work  of 
the  Survey.  The  corresponding  increase  in  personnel 
has  been  from  39,  listed  in  the  first  report,  to  911  holding 
regular  appointments  at  the  present  time,  divided  among 
the  different  branches  as  follows:  A  scientific  force  of 
173  in  the  Geologic  Branch,  169  in  the  Water  Resources 
Branch,  71  in  the  Topographic  Branch,  and  15  in  the 
Land  Classification  Board,  with  a  clerical  force  of  168 
divided  among  the  same  branches,  and  the  remainder 
the  technical  and  clerical  employees  of  the  publication 
and  administrative  branches.  These  personnel  statistics 
are  not  expressive  of  normal  conditions,  since  a  large 
number  of  the  topographic  engineers  are  commissioned 
officers  and  thus  are  not  included  on  the  civilian  roll, 
while,  on  the  other  hand,  the  classification  of  the  stock- 
raising  homestead  lands  makes  the  technical  force  of  the 
Water  Resources  Branch  unusually  large  this  year. 

The  primary  aim  of  the  Geological  Survey  is  geo- 
logic, whether  directed  by  authority  of  law  toward 
the  *' examination  of  the  geological  structure,  mineral 
resources,  and  products  of  the  national  domain,''  toward 
the  preparation  of  the  authorized  *^  reports  upon  gen- 
eral and  economic  geology  and  paleontology,"  of  the 
** geologic  map  of  the  United  States,''  or  of  the  '* report 
on  the  mineral  resources  of  the  United  States,"  or 
toward  the  *' continuation  of  the  investigation  of  the 
mineral  resources  of  Alaska"  or  ** chemical  and  physi- 
cal researches  relating  to  the  geology  of  the  United 
States."  The  spirit  and  the  purpose  of  the  Sur- 
vey's work  in  all  these  fields  are  not  believed  to  have 
materially  changed  from  those  of  the  founders  of  the 
science  in  America.  From  time  to  time  too  much  empha- 
sis may  have  appeared  to  be  laid  upon  applied  geology  as 
contrasted  with  pure  science,  yet  the  report  of  the 
National  Academy  to  Congress  in  terms  placed  the  stress 
upon  economic  resources  and  referred  to  paleontology  as 
'* necessarily  connected"  with  general  and  economic 
geology.  The  practical  purpose  of  geologic  research 
under  Government  auspices  must  be  recognized  by  the 
administrator,  whether  he  be  the  paleontologist  like  Wal- 


GOVERNMENT  GEOLOGICAL  SURVEYS     211 

cott,  the  philosopher  like  Powell,  or  the  mining  geologist 
like  King.  That  the  task  of  steering  the  true  course  is 
no  new  problem  can  be  seen  from  the  statement  of  Owen^<* 
written  70  years  ago,  and  these  words  describe  conditions 
of  Government  geological  work  even  to-day : 

Scientific  researches,  which  to  some  may  seem  purely  specu- 
lative and  curious,  are  essential  as  preliminaries  to  these 
practical  results.  Further  than  such  necessity  dictates,  they 
have  not  been  pushed,  except  as  subordinate  and  incidental, 
and  chiefly  at  such  periods  as,  under  the  ordinary  requirements 
of  public  service,  might  be  regarded  as  leisure  moments ;  so  that 
the  contributions  to  science  thus  incidentally  afforded,  and  which 
a  liberal  policy  forbade  to  neglect,  may  be  considered,  in  a 
measure,  a  voluntary  offering,  tendered  at  little  or  no  additional 
expense  to  the  department. 

The  increased  attention  given  to  mineral  resources  has 
been  a  matter  of  gradual  growth.  Mr.  King  early 
organized  a  Division  of  Mining  Geology  with  Messrs. 
Pumpelly,  Emmons,  and  Becker  as  geologists  in  charge, 
to  whom  were  assigned  the  collection  of  mineral  statis- 
tics for  the  Tenth  Census.  These  Survey  geologists  and 
Director  King  himself  held  appointments  as  special 
agents  of  the  Census  Bureau,  and  on  the  staff  selected  for 
this  work  appear  the  names  of  T.  B.  Brooks,  Edward 
Orton,  T.  C.  Chamberlin,  Eugene  A.  Smith,  George 
Little,  J.  R.  Proctor,  R.  D.  Irving,  N.  S.  Shaler, 
John  Hays  Hammond,  Bailey  Willis,  and  G.  H.  Eldridge, 
indicating  the  extent  to  which  the  supervision  of  these 
inquiries  was  placed  in  the  hands  of  economic  geologists. 
This  procedure  was  reverted  to  by  Director  Walcott  and 
in  the  last  ten  years  has  become  a  well-established  policy, 
the  statistics  of  annual  production  of  all  the  important 
mineral  products  being  under  the  charge  of  geologists,  as 
best  qualified  to  comprehend  the  resources  of  the  coun- 
try. Another  of  these  special  assistants  in  1880  was 
Albert  Williams,  Jr.,  who  became  the  first  chief  of  the 
Division  of  Mineral  Resources,  in  1882.  The  study  of 
ore  deposits,  which  may  be  said  to  have  begun  with  the 
King  Survey,  was  inspired  by  King's  own  appreciation 
of  the  broad  geologic  relations  of  the  distribution  of 
mineral  wealth  and  by  the  detailed  studies  of  individual 


212  A  CENTURY  OF  SCIENCE 

mining  districts  by  his  associates,  **  based  upon  facts 
accurately  determined  in  the  light  of  modern  geology. ' ' 

Geological  surveys  have  been  prosecuted  in  Alaska 
since  1895,  and  in  the  last  few  years  the  annual  appro- 
priation for  the  work  has  been  the  same  as  that  made  for 
the  expenses  of  the  whole  Survey  in  the  first  year  of  its 
history.  The  Division  of  Alaskan  Mineral  Resources  is  in 
fact  a  geological  survey  in  itself,  except  that  it  shares  in 
the  administrative  machinery  of  the  larger  organization 
and  has  the  advantage  of  the  cooperation  of  the  scientific 
specialists  of  the  Survey  as  they  may  be  needed  to  sup- 
plement its  own  force.  All  the  investigations  in  this  dis- 
tant part  of  the  country  represent  the  Geological  Survey 
at  its  best,  for  here  the  organization's  long  experience  in 
the  Western  States  can  be  applied  to  most  effective  and 
helpful  work  on  the  frontier,  where  the  geologist  and 
topographer  in  their  exploration  do  not  always  follow 
the  prospector  but  often  precede  him.  Undoubtedly  no 
greater  factor  has  contributed  to  the  development  of 
Alaskan  resources  than  this  pioneer  work  of  the  Federal 
Survey,  yet  the  work  has  also  contributed  notable  addi- 
tions to  the  sciences  of  geology  and  geography. 

The  first  duty  laid  upon  the  Director  of  the  Geological 
Survey  in  the  law  of  1879  was  **the  classification  of  the 
public  lands,"  and  this  phrase  undoubtedly  expressed  the 
idea  of  the  committee  of  the  National  Academy.  The 
same  legislation,  however,  contained  provision  for  the 
further  consideration  by  a  commission  of  the  classifica- 
tion and  valuation  of  the  public  lands,  as  also  recom- 
mended by  the  National  Academy.  Thus  the  decision  of 
Director  King  that  the  classification  intended  by  Con- 
gress was  scientific  and  was  intended  for  general  informa- 
tion and  not  to  aid  the  Land  Office  in  the  disposition  of 
land  by  sale  or  otherwise  was  really  based  upon  the 
deliberate  opinion  of  the  Public  Lands  Commission,  of 
which  he  was  a  member,  that  classification  would  seri- 
ously impede  rapid  settlement  of  the  unoccupied  lands. 
Nearly  forty  years  later  those  who  are  intrusted  with  the 
land-classification  work  of  the  Geological  Survey  recog- 
nize this  familiar  argument,  which  undoubtedly  had  much 
more  force  in  that  earlier  stage  of  the  utilization  of  the 


GOVERNMENT  GEOLOGICAL  SURVEYS     213 

Nation's  resources  of  land.^^  The  conception  of  land 
classification  as  a  business  policy  on  the  part  of  the  Gov- 
ernment as  a  landed  proprietor  belongs  rather  to  this 
day  of  more  intensive  development.  At  present  current 
public-land  legislation  calls  for  highest  use,  and  hence 
official  investigation  of  natural  values  and  possibilities 
must  precede  disposition.  This  type  of  mineral  and 
hydrographic  classification  of  public  lands  has  been  in 
progress  in  increasing  amount  since  1906,  so  that  now 
the  Geological  Survey  is  the  kind  of  scientific  adviser  to 
the  Secretary  of  the  Interior  and  Commissioner  of  the 
General  Land  Office  that  may  have  been  contemplated  by 
the  National  Academy  of  Sciences  in  1878.  It  is  plain, 
however,  to  everyone  at  all  conversant  with  Western  con- 
ditions that  the  recent  land-classification  surveys  in 
Wj^oming,  for  instance — detailed  geologic  surveys  which 
form  the  basis  for  the  valuation  of  public  coal  lands  in 
40-acre  units — would  have  possessed  no  utility  in  1871, 
when  the  coal-land  law  was  passed  but  when  the  demand 
for  railroad  fuel  had  just  begun. 

The  land-classification  idea  is  of  course  the  basis  of 
the  National  forest  and  irrigation  movements.  The  laws 
of  1888  and  1896,  which  mark  the  beginning  of  active 
endorsement  by  Congress  of  these  conservation  move- 
ments, placed  upon  the  Survey  the  duties  of  examining 
reservoir  sites  and  forest  reserves  respectively.  The 
earlier  of  these  laws  began  the  investigation  of  the  water 
resources  of  the  country,  which  is  still  an  important  phase 
of  the  Survey's  activity,  and  led  to  the  creation  of  an  inde- 
pendent organization — the  Reclamation  Service.  It  is 
easy  to  trace  the  beginnings  of  Federal  reclamation  of 
arid  lands  in  the  pioneer  work  of  Powell,  whose  report 
in  1878  on  the  arid  region  of  the  United  States  was  the 
first  adequate  statement  of  the  problem  of  largest  use  of 
these  lands  in  terms  broader  than  those  of  individual- 
istic endeavor.  For  years,  however,  Powell's  appeal  for 
Congressional  consideration  of  this  National  task  was 
like  the  ** voice  of  one  crying  in  the  wilderness." 

In  a  somewhat  similar  way  the  forestry  surveys  under 
the  Geological  Survey  helped  in  the  organization  of  a 
separate  bureau — now  the  Forest  Service.     The  other 


2U  A  CENTURY  OF  SCIENCE 

important  Federal  bureau  tracing  direct  relationship  to 
the  Survey  is  the  Bureau  of  Mines,  established  in  1910, 
which  continued  the  investigations  in  mining  technology 
specifically  provided  for  by  Congress  for  six  years  under 
the  Geological  Survey  but  in  some  degree  begun  in  the 
early  days  of  the  Survey  under  Directors  King  and 
Powell. 

Another  equally  important  organization  of  a  public 
nature,  though  not  a  Federal  bureau,  traces  its  begin- 
nings to  the  Geological  Survey :  the  Geophysical  Labora- 
tory of  the  Carnegie  Institution,  which  now  exercises  so 
potent  an  influence  over  geologic  investigation,  had  its 
origin  in  the  official  work  of  the  Geological  Survey's 
Division  of  Chemical  and  Physical  Research,  and  its  per- 
sonnel was  at  first  largely  recruited  from  the  Survey. 
The  highly  original  experimental  work  of  this  laboratoiy 
has  extended  far  beyond  the  scope  of  the  Survey's  work — 
at  least  far  beyond  the  scope  possible  with  the  Federal 
funds  available — yet  most  of  the  results  of  these  inves- 
tigations may  eventually  come  under  even  a  strict 
construction  of  the  language  used  in  the  Survey's  appro- 
priation **for  chemical  and  physical  researches  relating 
to  the  geology  of  the  United  States. ' ' 

The  topographic  work  of  the  present  Survey  continues 
with  constant  refinement  of  standards  and  economy  of 
methods  the  work  of  the  earlier  organizations.  The 
primary  purpose  of  these  topographic  surveys  is  to  pro- 
vide the  bases  for  geologic  maps,  yet  these  topographic 
maps,  which  cover  40  per  cent  of  the  area  of  the  United 
States,  are  used  in  every  type  of  civil  engineering  as  well 
as  by  the  public  generally.  The  annual  distribution  by 
sale  of  half  a  million  of  these  maps  is  an  index  of  their 
value  to  the  people. 

The  hot  discussion  that  was  waged  for  years  on  the 
question  of  military  versus  scientific  administration  of 
topographic  surveys  is  in  striking  contrast  with  the 
present  concentration  of  all  the  topographic  mapping 
under  the  Geological  Survey  in  those  areas  where  it  may 
best  serve  the  needs  of  the  Army.  In  1916  Congress 
specifically  recognized  the  possibility  of  greater  coop- 
eration of  this  kind,  both  in  the  appropriation  made  to 


GOYEENMENT  GEOLOGICAL  SURVEYS    215 

the  Geological  Survey  and  in  a  special  appropriation 
made  to  the  War  Department.  For  a  number  of  years 
indeed  special  military  information  had  been  contributed 
to  the  Army  by  the  Survey  topographers,  but  since 
March  26,  1917,  every  Geological  Survey  topographer 
has  worked  exclusively  on  the  program  of  military  sur- 
veys laid  down  by  the  General  Staff  of  the  Army,  and  the 
places  of  some  of  the  44  Survey  topographers  now  in 
France  as  engineer  officers  are  filled  by  34  other  reserve 
engineer  officers  detailed  by  order  of  the  Secretary  of 
War  to  the  Director  of  the  Geological  Survey  to  assist 
in  this  military  mapping  and  to  receive  instruction  fitting 
them  in  turn  for  topographic  service  in  France. 

The  contribution  of  this  civilian  service  to  the  military 
operations  in  the  present  emergency  forms  a  fitting  con- 
clusion to  this  review  of  a  century  of  Government  sur- 
veys. At  present  215  members  of  the  Geological  Survey 
are  in  uniform,  107  as  engineer  officers,  two  of  whom  are 
on  the  staff  of  the  American  Commanding  General  in 
France.  In  the  war  work  carried  on  in  the  United 
States  the  Survey's  contribution  is  by  no  means  limited 
to  military  mapping :  the  geologists  are  also  mobilized  for 
meeting  war  needs,  assisting  in  developing  new  sources 
of  the  essential  war  minerals,  in  speeding  up  production 
of  mineral  products,  in  collecting  information  for  the 
purchasing  officers  both  of  our  own  and  of  the  Allied  gov- 
ernments, in  cooperating  with  the  constructing  quarter- 
masters in  the  location  of  gravel  and  sand  for  structural 
use  and  in  both  general  and  special  examinations  of 
underground  water  supply  and  of  drainage  possibilities 
at  cantonment  sites,  and  in  supplying  the  Navy  Depart- 
ment with  similar  technical  data.  A  special  contribution 
has  been  the  application  to  aerial  surveys  of  photogram- 
metric  methods  developed  in  the  Alaskan  topographic 
work  and  the  perfection  of  a  camera  specially  adapted  to 
airplane  use.  The  utilization  of  the  Survey's  map 
engraving  and  printing  plant  for  confidential  and  urgent 
work  for  both  the  Army  and  Navy  has  necessitated  post- 
ponement of  current  work  for  the  Geological  Survey 
itself.  Throughout  the  organization  the  records,  the 
methods,  and  the  personnel  which  represent  the  product 


216  A  CENTURY  OF  SCIENCE 

of  many  years  of  scientific  activity  are  all  being  utilized ; 
thus  is  the  experience  of  the  past  translated  into  special 
service  in  the  present  crisis. 


Notes, 

^  Hess,  B.  H.,  Foundations  of  National  Prosperity,  p.  100. 

'Eeport  Nat  a  Museum,  1904,  pp.  189-733. 

« Featherstonhaugh,  J.  D.,  Am.  Geol.,  3,  220,  1889. 

*  Whitney,  Mineral  Wealth  of  the  United  States,  pp.  248-250. 

■*  Foster  and  Whitney,  31st  Cong.,  1st  session.  House  Doc.  69,  pp.  13-14, 
1850. 

'  First  Annual  Kept.  U.  S.  Geol.  Survey,  p.  4. 

^Wheeler,  Keport  3d  Internat'l  Geog.  Cong.,  p.  492,  1885. 

*  The  views  of  the  writer  on  ' '  natural  monopolies ' '  in  the  Government 
service  are  set  forth  in  an  address  delivered  at  the  centennial  celebration 
of  the  U.  S.  Coast  and  Geodetic  Survey,  April  5,  1916.  (See  Science,  vol. 
43,  pp.  659-665,  May  12,  1916.) 

*  For  correspondence  on  this  subject,  see  Minnesota  Geol.  Survey,  Eighth 
Ann.  Kept.,  1880,  p.  173. 

"  Owen,  D.  D.,  30th  Cong.,  1st  sess.,  Senate  Doc.  No.  57,  p.  7,  1848. 

"  This  essential  difference  between  present-day  requirements  and  the 
needs  of  earlier  generations  has  been  discussed  by  W.  C.  Mendenhall,  the 
geologist  in  charge  of  the  Land  Classification  Board  of  the  Geological 
Survey:    Proceedings  2d  Pan-American  Sci.  Cong.,  1915-16,  3,  761. 


VI 

ON  THE  DEVELOPMENT  OF  VERTEBRATE 
PALEONTOLOGY 

By  RICHARD  SWANN  LULIi 

Introduction* 

UNLIKE  its  sister  science  of  Invertebrate  Paleon- 
tology, which  has  been  approached  so  largely  from 
the  viewpoint  of  stratigraphic  geology,  that  of  the 
vertebrates  is  essentially  a  biologic  science,  having  its 
inception  in  the  masterly  work  of  Cuvier,  who  is  also  to 
be  regarded  as  the  founder  of  comparative  anatomy. 
For  long  decades,  vertebrate  paleontology  was  simply  a 
branch  of  comparative  anatomy  or  morphology  in  that  it 
dealt  almost  exclusively  with  the  form  and  other  pecul- 
iarities of  fossil  bones  and  teeth,  often  in  a  more  or  less 
fragmentary  condition,  very  little  or  no  attention  being 
paid  to  any  other  system  of  the  creature's  anatomy. 
Distribution  both  in  space  and  in  time  was  recorded,  but 
the  value  of  vertebrates  in  stratigraphy  was  still  to  be 
appreciated  and  has  hardly  yet  come  into  its  own.  It  is 
readily  seen,  therefore,  that  the  two  departments  of 
paleontology  did  not  enlist  the  same  workers  or  even  the 
same  type  of  investigators,  for  while  the  two  sciences  have 
much  in  common  and  should  have  more,  the  vertebratist 
must,  above  all  else,  be  a  morphologist,  with  a  keen 
appreciation  of  form,  and  a  mind  capable  of  retaining 
endless  structural  details  and  of  visualizing  as  a  whole 
what  may  be  known  only  in  part.  The  initial  work  of  the 
brilliant  Cuvier  set  so  high  a  standard  of  preparedness 
and  mental  equipment  that  as  a  consequence,  the  number 
of  those  engaged  in  vertebrate  research  has  never  been 
large  as  compared  with  the  workers  in  some  other 
branches  of  science,  but  the  results  achieved  by  the  few 


218  A  CENTURY  OF  SCIENCE 

who  have  consecrated  their  research  to  the  fossil  verte- 
brates has  been  in  the  main  of  a  high  order. 

At  first,  as  has  been  emphasized,  this  work  was  largely 
morphological,  dealing  both  with  the  individual  skeletal 
elements  and  later  with  the  bony  framework  as  a  whole. 
Then  came  the  endeavor  to  clothe  the  bones  with  sinews 
and  with  flesh — to  imagine,  in  other  words,  the  life- 
appearance  of  the  ages-departed  form — ^with  such  of  its 
habits  as  could  be  deduced  from  structure  of  body,  tooth, 
and  limb.  Next  came  the  working  out  of  systematic 
series  of  vertebrates  and  their  marshalling  into  species, 
genera,  and  larger  groups,  and  much  time  was  thus  spent, 
especially  when  rapid  discovery  brought  a  continual 
stream  of  new  forms  before  the  systematist,  and  hence 
some  appreciation  of  the  countless  hosts  of  bygone  crea- 
tures which  peopled  the  world  in  the  geologic  past.  This 
systematic  work,  however,  was  based  upon  the  most 
painstaking  morphologic  comparisons  and  so  the  science 
was  still  within  the  scope  of  comparative  anatomy. 

In  connection  with  taxonomic  research  came  increas- 
ingly tangible  evidence  in  favor  of  the  law  of  evolution; 
investigators  turned  to  the  working  out  of  phyletic  series 
showing  the  actual  record  of  the  successive  evolutionary 
changes  that  the  various  races  had  undergone.  Coupled 
with  this  evolutionary  evidence  came  an  increased  atten- 
tion to  the  sequential  occurrence  in  successive  geologic 
strata,  and  the  stratigraphic  distribution  of  vertebrates 
became  known  with  greater  and  greater  detail.  Then 
followed  the  assemblage  of  faunas,  which  brought  the 
study  of  the  fossil  forms  within  the  realm  of  historical 
geology,  rather  than  being  the  mere  phylogeny  of  a  single 
race,  and  the  value  of  vertebrate  fossils  as  horizon 
markers  became  more  and  more  appreciated  by  the  stra- 
tigrapher.  They  serve  to  supplement  the  knowledge 
gained  from  the  invertebrates,  and  in  this  connection  are 
especially  valuable  in  that  they  often  give  data  concern- 
ing continental  formations  about  which  invertebrate 
paleontology  is  largely  silent. 

Mise  of  Vertebrate  Paleontology  in  Europe, 

To  those  who  had  been  nurtured  in  the  belief  in  a  rela- 
tively recent  creation  covering  in  its  entirety  a  period  of 


VERTEBRATE  PALEONTOLOGY     219 

but  six  days,  and  occurring  but  four  millenniums  before 
the  time  of  Christ,  the  appearance  of  the  remains  of 
creatures  in  the  rocks,  the  like  of  which  no  man  ever  saw 
alive,  must  have  given  scope  to  the  wildest  imaginings 
concerning  their  origin  and  significance;  for  many- 
believed  that  not  only  had  no  new  forms  been  added  to 
the  world's  fauna  since  the  creation,  except  possibly  by 
hybridizing,  but  that  none  had  become  extinct  save  a  very 
few  through  the  agency  of  human  interference.  The 
supposition  was,  therefore,  that  such  creatures  as  were 
thus  discovered  were  still  extant  in  some  more  remote 
fastnesses  of  the  world.  Thus,  our  second  president, 
Thomas  Jefferson,  who  wrote  one  of  the  first  papers  on 
American  fossil  vertebrates,  published  in  1798,  discussed 
therein  the  remains  of  a  huge  ground-sloth  which  has 
since  borne  the  name  Megalonyx  jeffersoni,  Jefferson, 
however,  described  the  great  claws  as  pertaining  to  a 
huge  leonine  animal  which  he  firmly  believed  was  yet 
living  among  the  mountains  of  Virginia. 

Cuvier  (1769-1832)  has  been  spoken  of  as  the  founder 
of  our  science.  His  opportunity  lay  in  the  profusion  of 
bones  buried  in  the  gypsum  deposits  of  Montmartre 
within  the  environs  of  the  city  of  Paris.  Cuvier 's 
studies  of  these  remains,  done  in  the  light  of  his  very 
broad  anatomical  knowledge,  enabled  him  to  prepare  the 
first  reconstructions  of  fossil  vertebrates  ever  attempted 
and  to  bring  before  the  eyes  of  his  contemporaries  a 
world  peopled  with  forms  which  were  utterly  extinct. 
That  these  creatures  were  no  longer  living,  none  was  a 
better  judge  than  Cuvier,  for  his  prominence  was  such 
that  material  was  sent  him  from  all  parts  of  the  world,  to 
which  must  be  added  that  which  he  saw  in  his  visits  to 
the  various  museums  of  Europe.  He  felt  it  safe,  there- 
fore, to  affirm  the  unlikelihood  of  any  further  discovery 
of  unknown  forms  among  the  great  mammals  of  the  pres- 
ent fauna  of  our  globe,  and  few  indeed  have  been  the 
additions  since  his  day.  To  Cuvier  is  due  not  alone  the 
masterly  contribution  to  the  sister  sciences  of  compara- 
tive anatomy  and  vertebrate  paleontology — the  Osse- 
ments  Fossiles  (1812) — but  he  also  announced  the 
presence  in  continental  strata  of  a  series  of  faunas  which 
showed  a  gradual  organic  improvement  from  the  earliest 


220  A  CENTUEY  OF  SCIENCE 

such  assemblage  to  the  most  modern,  an  idea  of  the  most 
fundamental  importance  and  one  with  which  he  is  rarely 
credited.  He  believed  in  the  sudden  and  complete 
extinction  of  faunas,  and  the  facts  then  known  were  in 
accord  with  this  idea,  as  no  common  genera  nor  transi- 
tional forms  connected  the  creatures  of  the  Paris  gypsum 
with  the  mastodons,  elephants,  and  hippopotami  which 
the  later  strata  disclosed.  It  is  not  remarkable,  there- 
fore, that  Cuvier  advanced  his  theory  of  catastrophism  to 
account  for  these  extinctions.  He  should  not,  however, 
according  to  Deperet,  be  credited  with  the  idea  of  suc- 
cessive re-creations,  such  as  that  held  by  D'Orbigny  and 
others,  but  of  repopulation  by  immigration  from  some 
area  which  the  catastrophe,  be  it  flood  or  other  destruc- 
tive agency,  failed  to  reach. 

Cuvier  was  followed  in  Europe  by  a  number  of  illus- 
trious men,  none  of  whom,  however,  with  the  exception  of 
Sir  Richard  Owen,  possessed  his  breadth  of  knowledge 
of  comparative  anatomy  upon  which  to  base  their 
researches  among  the  prehistoric.  The  more  notable  of 
them  may  be  enumerated  before  going  on  to  a  discussion 
of  the  American  contributions  to  the  science. 

They  were,  first,  Louis  Agassiz,  a  pupil  of  Cuvier  and 
later  a  resident  of  America,  whose  researches  on  the  fos- 
sil fishes  of  Europe  are  a  monumental  work,  the  result  of 
ten  years  of  investigation  in  all  of  the  larger  museums  of 
that  continent,  and  which  appeared  in  1833-43,  while  he 
was  yet  a  young  man.  The  fishes  were  practically  the 
only  fossil  vertebrates  to  come  within  the  scope  of  his 
investigations,  for  his  later  time  was  Consumed  in  the 
study  of  glaciers  and  of  recent  marine  zoology.  Another 
student  of  these  most  primitive  vertebrates  who  left 
an  enduring  monument  was  Johannes  Miiller.  Huxley, 
Traquair,  and  Jaekel  also  did  masterly  work  upon  this 
group,  while  Smith  Woodward  of  the  British  Museum  is 
considered  the  highest  living  authority  upon  fossil  fishes. 

Of  the  Amphibia,  the  most  famous  foreign  students 
were  Brongniart,  Jaeger,  Burmeister,  Von  Meyer,  and 
Owen,  although  Owen's  claim  to  eminence  lies  rather  in 
the  investigations  of  fossil  reptiles  which  he  began  in 
1839  and  continued  over  a  period  of  fifty  years  of 
remarkable  achievement.    Not  only  did  he  describe  the 


VERTEBRATE  PALEONTOLOGY     221 

dinosaurs  of  Great  Britain  in  a  series  of  splendidly  illus- 
trated monographs,  but  extended  his  researches  to  the 
curious  reptilian  forms  from  the  Karroo  formation  of 
South  Africa.  It  was  to  him,  moreover,  that  the  estab- 
lishment of  the  true  position  of  the  famous  Archceopteryx 
as  the  earliest  known  bird  and  not  a  reptile  is  due.  Von 
Meyer  also  enriched  the  literature  of  fossil  reptiles, 
discussing  exhaustively  those  occurring  in  Germany, 
while  Huxley's  classic  work  on  the  crocodiles  as  well  as 
on  dinosaurs,  and  the  labors  of  Buckland,  Fraas,  Koken, 
Von  Huene,  Gaudry,  Hulke,  Seeley,  and  Lydekker  have 
added  immensely  to  our  knowledge  of  the  group. 

Of  the  birds,  which  at  best  are  rare  as  fossils,  our 
knowledge,  especially  of  the  huge  flightless  moas,  is  due 
largely  again  to  Owen,  and  his  realization  of  the  syste- 
matic position  of  Archceopteryx  has  already  been  men- 
tioned. 

The  mammals  were,  perhaps,  the  most  prolific  source 
of  paleontological  research  during  the  nineteenth  cen- 
tury, for,  as  Zittel  has  said,  Cuvier's  famous  investiga- 
tions ^on  the  fossil  bones,  mentioned  above,  not  only 
contain  the  principles  of  comparative  osteology,  but  also 
show  in  a  manner  which  has  never  been  surpassed  how 
fossil  vertebrates  ought  to  be  studied,  and  what  are  the 
broad  inductions  which  may  be  drawn  from  a  series  of 
methodical  observations.  Such  was  Cuvier's  influence 
that  until  Darwin  began  to  interest  himself  in  mammalian 
paleontology  the  study  of  these  forms  was  conducted 
entirely  along  the  lines  indicated  by  the  French  savant. 
This  was  seen  in  a  large  work.  Osteology  of  Recent  and 
Fossil  Mammalia,  by  De  Blainville,  which,  although  not 
up  to  the  standard  set  by  the  master,  is  nevertheless  a 
notable  contribution,  as  was  also  the  Osteology  prepared 
by  Pander  and  D  'Alton.  A  summary  of  the  knowledge  of 
the  fossil  Mammalia  up  to  the  year  1847  is  contained  in 
Giebel's  Fauna  der  Vorwelt,  and  Lydekker  has  done  for 
the  mammals  in  the  British  Museum  what  Smith  Wood- 
ward did  for  the  fishes,  producing  vastly  more  than  the 
mere  catalogue  which  the  title  implies. 

The  first  work  wherein  the  fossil  mammals  were 
treated  genealogically  was  Gaudry 's  Enchainements  du 
Monde  Animal,  written  in  1878.     Other  work  on  the 

14 


222  A  CENTURY  OF  SCIENCE 

fossil  Mammalia  was  done  by  Kaup,  who  described  those 
from  the  Mainz  basin  and  from  Epplesheim  near  Worms 
whence  came  one  of  the  most  famous  of  prehistoric 
horses,  the  Hipparion;  this  horse,  together  with  the 
remarkable  proboscidean  Dinotherium,  was  described  by 
Von  Meyer.  One  of  the  most  remarkable  discoveries, 
ranking  in  importance,  perhaps,  next  to  Montmartre,  was 
that  of  the  Pliocene  fauna  of  Pikermi  near  Athens, 
Greece,  first  made  known  through  the  publications  of  A. 
Wagner  of  Munich  and  later,  and  much  more  extensively, 
through  that  of  Gaudry  (1862-1867).  H.  von  Meyer  was 
Germany's  best  authority  on  fossil  Mammalia.  After 
his  death  the  work  was  carried  on  by  Quenstedt,  Oscar 
Fraas,  Schlosser,  Koken,  and  Pohlig,  among  others. 

In  France,  rich  deposits  of  fossil  mammals  were  dis- 
covered in  the  Department  of  Puy-de-D6me,  the  Rhone 
basin,  Sansan,  Quercy,  and  near  Rheims.  These  were 
described  by  a  number  of  writers,  notably  Croizet  and 
Jobert,  Pomel,  Lartet,  Filhol,  and  Lemoine. 

Riitimeyer  of  Bale  was  one  of  the  most  famous  Euro- 
pean writers  on  mammalian  paleontology,  and  his 
researches  were  both  comprehensive  and  clothed  in  such 
form  as  to  give  them  a  high  place  in  paleontological  lit- 
erature. He  studied  comparatively  the  teeth  of  ungu- 
lates, discussed  the  genealogy  of  mammals,  and  the 
relationships  of  those  of  the  Old  and  New  Worlds.  He 
was  an  exponent  of  the  law  of  evolution  as  set  forth  by 
Darwin,  and  his  **  genealogical  trees  of  the  Mammalia 
show  a  complete  knowledge  of  all  the  data  concerning  the 
different  members  in  the  succession,  and  are  amongst  the 
finest  results  hitherto  obtained  by  means  of  strict  scien- 
tific methods  of  investigation''  (Zittel,  History  of  Geol- 
ogy and  Palaeontology,  1901).  The  mammals  of  the 
Swiss  Eocene  have  been  studied  in  much  detail  by 
Stehlin. 

For  Great  Britain,  the  most  notable  contributors  were 
Buckland  in  his  Reliquiae  Diluvianae ;  Falconer,  co-author 
with  Cautley  on  the  Tertiary  mammals  of  India ;  Charles 
Murchison,  who  wrote  on  rhinoceroses  and  probosci- 
deans ;  and  more  recently  Bush,  Flower,  Lydekker,  Boyd 
Dawkins,  L.  Adams,  and  C.  W.  Andrews.  But  by  far  the 
most  commanding  figure  of  all  was  Sir  Richard  Owen, 


VERTEBRATE  PALEONTOLOGY     223 

who  for  half  a  century  stood  without  a  peer  as  the 
greatest  of  authorities  on  fossil  mammals.  It  was  the 
Natural  History  of  the  British  Fossil  Mammals  and 
Birds,  published  in  1846,  that  established  Sir  Richard's 
reputation. 

Russia  has  produced  much  mammalian  material, 
especially  from  the  Tertiary  of  Odessa  and  Bessarabia, 
and  from  the  Quaternary  of  northern  Russia  and  Siberia. 
These  have  been  described  mainly  by  J.  F.  Brandt,  A. 
von  Nordmann,  but  especially  by  Mme.  M.  Pavlow  of 
Moscow. 

Forsyth-Major  discovered  in  1887  a  fauna  contem- 
poraneous with  that  of  Pikermi  in  the  Island  of  Samos 
in  the  Mediterranean. 

One  of  the  most  remarkable  recent  discoveries  of  fossil 
localities  was  that  announced  in  1901  by  Mr.  Hugh  J.  L. 
Beadnell  of  the  Geological  Survey  of  Egypt  and  Doctor 
C.  W.  Andrews  of  the  British  Museum  of  London,  of 
numerous  land  and  sea  mammals  of  Upper  Eocene  and 
Lower  Oligocene  age  in  northern  Egypt.  The  exposures 
lay  about  80  miles  southwest  of  Cairo  in  the  Fayum  dis- 
trict and  are  the  sediments  of  an  ancient  Tertiary  lake,  a 
relic  of  which,  Birket-el-Qurun,  yet  remains.  These  beds 
contained  ancient  Hyracoidea,  Sirenia,  and  Zeuglodontia, 
but  above  all,  ancestral  Proboscidea  which,  together  with 
those  known  elsewhere,  enabled  Andrews  to  demonstrate 
the  origin  and  evolutionary  features  of  this  most  remark- 
able group  of  beasts.  This  discovery  in  the  Fayum  lends 
color  to  the  belief  that  Africa  may  have  been  the  ancestral 
home  of  at  least  ^ve  of  the  mammalian  orders,  those  men- 
tioned above,  together  with  the  Embrithopoda,  a  group 
unknown  elsewhere.  This  theory  had  been  advanced 
independently  by  Tullberg,  Stehlin,  and  Osborn,  before 
the  discovery  in  Egypt. 

Another  European  worker  of  pre-eminence  who  wrote 
more  broadly  than  the  faunal  studies  mentioned  above 
was  W.  Kowalewsky.  He  discussed  especially  the  evo- 
lutionary changes  of  feet  and  teeth  in  ungulates,  a  line  of 
research  afterward  developed  in  greater  detail  by  the 
Americans,  Cope  and  Osborn. 

South  America  has  yielded  series  of  rich  faunas  which 
have  been  exploited  by  the  great  Argentinian,  Florentino 


224:  A  CENTUEY  OF  SCIENCE 

Ameghino,  and  by  the  Europeans,  Owen,  Gervais,  Hux- 
ley, Von  Meyer,  and  more  recently  by  Burmeister  and 
Lydekker.  Later  exploration  and  research  by  Hatcher 
and  Scott  of  North  America  will  be  discussed  further  on 
in  this  paper. 

Vertebrate  Paleontology  in  America. 

Early  Writers, — Having  thus  summarized  paleontolog- 
ical  progress  in  the  Old  World,  we  can  turn  to  a  consid- 
eration of  the  work  done  in  the  New,  especially  in  the 
United  States,  because  while  the  Old  World  investigation 
has  been  invaluable,  a  science  of  vertebrate  paleontology, 
very  complete  both  as  to  its  zoological  and  geological 
scope  and  in  the  extent  and  value  of  published  results, 
could  be  built  exclusively  upon  the  discoveries  and 
researches  made  by  Americans.  The  science  of  verte- 
brate paleontology  may  be  said  to  have  had  its  beginnings 
in  North  America  with  the  activities  of  Thomas  Jeffer- 
son, who,  like  Franklin,  felt  so  strong  an  interest  in 
scientific  pursuits  that  even  the  graver  duties  of  the  high- 
est office  in  the  gift  of  the  American  people  could  not 
deter  him  from  them.  When  in  1797  Jefferson  came  to 
be  inaugurated  as  vice-president  of  the  United  States,  he 
brought  with  him  to  Philadelphia  not  only  his  manuscript 
but  the  actual  fossil  bones  upon  which  it  was  based. 
Again  in  1801  he  was  greatly  interested  in  the  Shawan- 
gunk  mastodon,  despite  heavy  cares  of  state,  and  in  1808 
made  part  of  the  executive  mansion  in  Washington  serve 
as  a  paleontological  laboratory,  displaying  therein  for 
study  the  bones  of  proboscideans  and  their  contempora- 
ries which  the  Big  Bone  Lick  of  Kentucl^  had  produced. 
Jefferson's  work  would  not,  perhaps,  have  been  epoch- 
making  were  it  not  for  its  unique  chronological  position 
in  the  annals  of  the  science. 

Jefferson  was  followed  by  another  man — this  time  one 
whose  diverging  lines  of  interest  led  him  not  into  the 
realm  of  political  service,  but  of  art,  for  Rembrandt 
Peale  possessed  an  enviable  reputation  among  the  early 
painters  of  America.  Peale  published  in  1802  an  account 
of  the  skeleton  of  the  ** mammoth,"  really  the  mastodon, 
M.  americanus,  speaking  of  it  as  a  nondescript  carnivor- 


VERTEBRATE  PALEONTOLOGY     225 

ous  animal  of  immense  size  found  in  America.  It  was 
because  of  the  form  of  the  molar  teeth  that  Peale  said  of 
it:  **If  this  animal  was  indeed  carnivorous,  which  I 
believe  cannot  be  doubted,  though  we  may  as  philoso- 
phers regret  it,  as  men  we  cannot  but  thank  Heaven  that 
its  whole  generation  is  probably  extinct. ' ' 

With  the  work  of  these  men  as  a  beginning,  it  is  not 
strange  that  the  more  conspicuous  Pleistocene  fossils  of 
the  East  should  have  attracted  the  attention  of  many 
subsequent  writers  in  the  first  part  of  the  nineteenth  cen- 
tury, nor  that  the  early  papers  to  appear  in  the  Journal 
should  pertain  to  proboscideans  or  to  the  huge  edentate 
ground-sloths  and  the  aberrant  zeuglodons  whose  bones 
frequently  came  to  light.  Therefore  a  number  of  men 
such  as  Koch,  both  Sillimans,  J.  C.  Warren,  and  others 
made  these  forms  their  chief  concern. 

Fossil  Footprints. — Among  the  early  writers  who  con- 
cerned themselves  with  these  greater  fossils  was  Edward 
Hitchcock,  sometime  president  of  Amherst  College,  and 
a  geologist  of  high  repute  among  his  contemporaries. 
Hitchcock  is,  however,  better  and  more  widely  known  as 
the  pioneer  worker  on  a  series  of  phenomena  displayed 
as  in  no  other  place  in  the  region  in  which  he  made  his 
home.  These  are  fossil  footprints  impressed  upon  the 
Triassic  rocks  of  the  Connecticut  valley.  It  was  in  the 
Journal  for  the  year  1836  (29,  307-340)  that  Hitchcock 
first  called  attention  to  the  footmarks,  although  they  had 
been  known  and  discussed  popularly  for  a  number  of 
years  previous.  James  Deane,  of  Greenfield,  was  per- 
haps the  first  to  appreciate  the  scientific  interest  of  these 
phenomena,  but  deeming  his  own  qualifications  insuffi- 
cient properly  to  describe  them,  he  brought  them  to  the 
attention  of  Hitchcock,  and  the  interest  of  the  latter 
never  waned  until  his  death  in  1864.  Hitchcock  wrote 
paper  after  paper,  publishing  many  of  them  in  the  Jour- 
nal, again  in  his  Final  Report  on  the  Geology  of  Massa- 
chusetts (1841),  and  later  in  quarto  works,  one  in  the 
Memoirs  of  the  American  Academy  of  Arts  and  Sciences 
and  the  two  others  under  the  authority  of  the  Common- 
wealth, the  Ichnology  in  1858,  and  the  Supplement  in 
1865,  the  last  being  a  posthumous  work  edited  by  his  son, 
Charles  H.  Hitchcock. 


226  A  CENTURY  OF  SCIENCE 

Hitchcock's  conception  of  the  track-makers  was  more 
or  less  imperfect  because  of  the  fact  that  for  a  long  time 
but  a  few  fragmentary  osseous  remains  were  known, 
either  directly  or  indirectly  associated  with  the  tracks, 
while  on  the  other  hand  the  bird-like  character  of  many 
of  the  latter  and  the  discovery  of  huge  flightless  birds 
elsewhere  on  the  globe  suggested  a  very  close  analogy  if 
not  a  direct  relationship.  Hence  *^bird  tracks''  they 
were  straightway  called,  a  designation  which  it  has  been 
dilBficult  to  remove,  even  though  in  1843  Owen  called  atten- 
tion to  the  need  of  caution  in  assuming  the  existence  of 
so  highly  organized  birds  at  so  early  a  period,  especially 
when  large  reptiles  were  known  which  might  readily 
form  very  similar  tracks.  The  footprints  are  now 
believed  to  be  very  largely  of  dinosaurian  origin,  and 
dinosaurs  whose  feet  corresponded  in  every  detail  with 
the  footprints  have  actually  come  to  light  within  the  same 
geologic  and  geographic  limitations.  This  of  course 
refers  to  the  bipedal,  functionally  three-toed  tracks.  Of 
the  makers  of  certain  of  the  obscurer  of  the  quadrupedal 
trails  we  are  as  much  in  the  dark  to-day  as  were  the 
first  discoverers  of  a  century  ago,  so  far  as  demonstrable 
proof  is  concerned.  We  assume,  however,  that  they  were 
the  tracks  of  amphibia  and  reptiles,  beyond  which  we  may 
not  go  with  certainty. 

Agassiz,  writing  in  1865  (Geological  Sketches),  says: 

**To  sum  up  my  opinion  respecting  these  footmarks,  I  believe 
that  they  were  made  by  animals  of  a  prophetic  type,  belonging 
to  the  class  of  reptiles,  and  exhibiting  many  synthetic  charac- 
ters. The  more  closely  we  study  past  creations,  the  more 
impressive  and  significant  do  the  synthetic  types,  presenting 
features  of  the  higher  classes  under  the  guise  of  the  lower  ones, 
become.  They  hold  the  promise  of  the  future.  As  the  opening 
overture  of  an  opera  contains  all  the  musical  elements  to  be 
therein  developed,  so  this  living  prelude  of  the  creative  work 
comprises  all  the  organic  elements  to  be  successively  developed 
in  the  course  of  time." 

Of  those  whose  work  was  contemporaneous  with  that 
of  Hitchcock,  but  one,  W.  C.  Redfield,  wrote  on  Triassic 
phenomena,  and  he  concerned  himself  mainly  with  the 
fossil  fishes  of  that  time,  his  first  paper  on  this  subject 


VERTEBRATE  PALEONTOLOGY     227 

appearing  in  1837  in  the  Journal  (34,  201),  and  the  last 
twenty  years  later. 

Paleozoic  Vertebrates. — Later  the  vertebrates  of  the 
Paleozoic  began  to  attract  attention,  footprints  from 
Pennsylvania  being  described  by  Isaac  Lea,  beginning  in 
1849,  a  notice  of  his  first  paper  appearing  in  the  Journal 
for  that  year  (9,  124).  Several  papers  followed  on  the 
reptile  Clepsysaurus,  Alfred  King  also  wrote  on  the 
Carboniferous  ichnites,  his  work  slightly  antedating  that 
of  Lea,  but  being  less  authoritative. 

But  by  far  the  most  illuminating  of  the  mid-century 
writers  on  Paleozoic  vertebrates  was  Sir  William  Daw- 
son, a  very  large  proportion  of  whose  numerous  papers 
relate  to  the  Coal  Measures  of  Nova  Scotia  and  their 
contained  plant  and  animal  remains.  In  1853  appeared 
Dawson's  first  announcement,  written  in  collaboration 
with  Sir  Charles  Lyell,  of  the  finding  of  the  bones  of 
vertebrates  within  the  base  of  an  upright  fossil  tree  trunk 
at  South  Joggins.  These  bones  were  identified  by  Owen 
and  Wyman  as  pertaining  to  a  reptilian  or  amphibian  to 
which  the  name  Dendrerpeton  acadianum  was  given. 
Following  this  were  several  papers  published  in  the 
Quarterly  Journal  of  the  Geological  Society,  London, 
describing  more  vertebrates  and  associated  terrestrial 
molluscs.  In  1863  Dawson  summarized  his  discoveries 
in  the  Journal  (36,  430-432)  under  the  title  of  **Air- 
breathers  of  the  Coal  Period/'  a  paper  which  was 
expanded  and  published  under  the  same  title  in  the  Cana- 
dian Naturalist  and  Geologist  for  the  same  year.  Daw- 
son also  printed  in  the  same  volume  the  first  account  of 
reptilian(?)  footprints  from  the  coal.  Thus  from  time 
to  time  there  emanated  from  his  prolific  pen  the  account 
of  further  discoveries,  both  in  bones  and  footprints,  his 
final  synopsis  of  the  air-breathing  animals  of  the  Paleo- 
zoic of  Canada  appearing  in  1895.  The  only  other  group 
of  vertebrates  which  claimed  his  attention  were  certain 
whales,  on  which  he  occasionally  wrote. 

Fishes. — The  fossil  fishes  from  the  Devonian  of  Ohio 
found  their  first  exponent  in  J.  S.  Newberry,  appointed 
chief  geologist  of  the  second  geological  survey  of  Ohio, 
which  was  established  in  1869.  These  fishes  from  the 
Devonian  shales  belonged  for  the  greater  part  to  the 


228  A  CENTUEY  OF  SCIENCE 

curious  group  of  armored  placoderms,  the  remains  of 
which  consist  very  largely  of  armor  plates  with  little  or 
no  traces  of  internal  skeleton.  There  was  also  found  in 
association  a  shark,  Cladoselache,  of  such  marvelous 
preservation  that  from  some  of  the  Newberry  specimens 
now  in  the  American  Museum  of  Natural  History,  New 
York,  Bashford  Dean  has  demonstrated  the  histology  of 
muscle  and  visceral  organs,  in  addition  to  the  very  com- 
plete skeletal  remains. 

Newberry's  work  on  these  forms,  begun  in  1868,  has 
been  carried  to  further  completion  by  Bashford  Dean  and 
his  pupil  L.  Hussakof,  as  well  as  by  C.  R.  Eastman. 
Newberry's  other  paleontological  work  was  with  the  Car- 
boniferous fishes  of  Ohio,  the  Carboniferous  and  Triassic 
fishes  of  the  region  from  Sante  Fe  to  the  Grand  and 
Green  rivers,  Colorado,  and  on  the  fishes  and  plants  of 
the  Newark  system  of  the  Connecticut  valley  and  New 
Jersey.  He  also  discussed  certain  mastodon  and  mam- 
moth remains,  and  those  of  the  peccary  of  Ohio, 
Dicotyles. 

Joseph  Leidy  (1823-1891), 

We  now  come  to  a  consideration  of  the  work  of  Joseph 
Leidy,  one  of  the  three  great  pioneers  in  American  verte- 
brate paleontology,  for  if  we  disregard  the  work  of  Hitch- 
cock and  others  on  the  fossil  footprints,  few  of  the  results 
thus  far  obtained  w^ere  based  upon  the  fruits  of  organized 
research.  Leidy  began  his  publication  in  1847  and  con- 
tinued to  issue  papers  and  books  from  time  to  time  until 
the  year  1892,  having  published  no  fewer  than  219  paleon- 
tological titles,  and  553  all  told.  His  earlier  paleontolog- 
ical researches  were  exclusively  on  the  Mammalia,  which 
were  then  coming  in  from  the  newly  discovered  fossil 
localities  of  the  West.  The  discovery  of  these  forms, 
one  of  the  most  notable  events  in  the  history  of  our 
science,  will  bear  re-telling. 

The  first  announcement  was  made  in  1847,  when  Hiram 
A.  Prout  of  St.  Louis  published  in  the  Journal  (3,  248- 
250)  the  description  of  the  maxillary  bone  of  ''Palceo- 
tJierium''  {=T  it  another  ium  proutii)  from  near  White 
River,  Nebraska.  This  at  once  drew  the  attention  of 
geologists   and  paleontologists  to   the  Bad  Lands,   or 


VERTEBRATE  PALEONTOLOGY     229 

Mauvaises  Terres,  which  were  to  prove  so  highly  produc- 
tive of  fossil  forms.  About  the  same  time  S.  D.  Culbert- 
son  of  Chambersburg,  Pennsylvania,  submitted  to  the 
Academy  of  Natural  Sciences  at  Philadelphia  some  fos- 
sils sent  to  him  from  Nebraska  by  Alexander  Culbertson. 
These  were  afterward  described  by  Leidy  in  the  Pro- 
ceedings of  the  Academy,  together  with  the  paleotheroid 
jaw,  in  addition  to  which  three  other  collections  which 
had  been  made  were  also  placed  at  hi§  disposal  for  study. 

This  aroused  the  interest  of  Doctor  Spencer  F.  Baird 
of  the  Smithsonian  Institution,  who  sent  T.  A.  Culbert- 
son to  the  Bad  Lands  to  make  further  collections.  The 
latter  was  successful  in  securing  a  valuable  series  of 
mammalian  and  chelonian  remains.  These,  together 
with  other  specimens  from  the  same  locality,  were  sent 
to  Leidy,  for,  as  Baird  remarked,  Leidy,  although  only 
thirty  years  of  age,  was  the  only  anatomist  in  the  United 
States  qualified  to  determine  their  nature.  The  outcome 
of  Leidy 's  study  of  this  material  was  **The  Ancient 
Fauna  of  Nebraska,"  published  in  1853,  and  constituting 
the  most  brilliant  work  which  up  to  that  time  American 
paleontology  had  produced.  Leidy 's  determinations, 
which  are  in  the  main  correct,  are  the  more  remarkable 
when  it  is  realized  that  he  had  little  recent  osteolog- 
ical  material  for  comparative  study.  The  forms  thus 
described  by  him  were  new  to  science,  of  a  more  gener- 
alized character  than  those  now  living,  and  yet  their 
distinguished  describer  recognized,  either  at  that  time  or 
a  little  later,  their  true  relationship  to  the  modern  types. 
The  extent  of  Leidy 's  anatomical  knowledge  was  almost 
Cuvierian,  and  Cuvier-like  he  established  the  fact  of  the 
presence  of  the  rhinoceroses,  then  unheard  of  in  the 
American  fauna,  from  a  few  small  fragments  of  molar 
teeth,  an  opinion  shortly  to  be  fully  sustained  through  the 
finding  of  complete  molars  and  the  entire  skull  of  the 
same  individual  animal, 

Leidy  next  turned  his  attention  to  the  huge  edentates, 
which  he  studied  exhaustively,  publishing  his  results  in 
the  form  of  a  memoir  in  1855,  two  years  after  the  appear- 
ance of  the  ** Ancient  Fauna." 

Extinct  fishes  of  the  Devonian  of  Illinois  and  Missouri 
and  the  Devonian  and  Carboniferous  of  Pennsylvania 


230  A  CENTURY  OF  SCIENCE 

were  made  the  subjects  of  his  next  researches,  after 
which  he  described  the  peccaries  of  Ohio,  and  later,  in  a 
much  larger  and  most  important  work,  the  Cretaceous 
reptiles  of  the  United  States  (1865).  Most  of  the  fossils 
discussed  in  this  last  work  are  from  the  New  Jersey  Cre- 
taceous marls  and  of  them  the  most  notable  was  the 
herbivorous  dinosaur  Hadrosaurus,  the  structure  and 
habits  of  which,  together  with  its  affinities  with  the  Old 
World  iguanodons,  Leidy  described  in  detail.  From 
Leidy's  descriptions  and  with  his  aid,  Waterhouse  Haw- 
kins was  enabled  to  restore  a  replica  of  the  skeleton  in  a 
remarkably  efficient  way.  This  restoration  for  a  long 
time  graced  the  museum  of  the  Philadelphia  Academy  of 
Natural  Sciences  and  there  was  a  plaster  replica  of  it  in 
the  United  States  National  Museum.  These,  together 
with  plaster  replicas  of  Iguanodon  from,  the  Eoyal  Col- 
lege of  Surgeons  in  London,  gave  to  Americans  their  first 
real  conceptions  of  members  of  this  most  remarkable 
group.  The  associated  fossils  from  the  New  Jersey 
marls  were  chiefly  crocodiles  and  turtles. 

From  1853  to  1866  F.  V.  Hayden  was  carrying  on  a 
series  of  most  energetic  explorations  in  the  West, 
especially  in  Nebraska  and  Dakota  as  then  delimited, 
returning  from  each  trip  laden  with  fossils  which  were 
given  to  Leidy  for  determination.  The  results  appeared 
in  1869  in  Leidy 's  Extinct  Mammalian  Fauna  of  Dakota 
and  Nebraska,  published  as  volume  7  of  the  Journal  of 
the  Philadelphia  Academy.  In  this  large  volume  no  fewer 
than  seventy  genera  and  numerous  species  of  forms, 
many  of  them  new  to  science,  were  described,  repre- 
senting many  of  the  principal  mammalian  orders ;  horses 
were,  however,  especially  conspicuous.  This  last  group 
led  Leidy  to  the  conclusion,  afterward  emphasized  by 
Huxley,  that  North  America  was  the  home  of  the  horse  in 
geologic  time,  there  being  here  a  greater  representation 
of  different  species  than  in  any  recent  fauna  of  the 
world.  Leidy 's  interest  in  the  horses,  for  the  forward- 
ing of  which  he  made  a  large  collection  of  recent  mate- 
rial, extended  over  many  years,  as  his  first  paper  on  the 
subject  bears  the  date  of  1847,  the  last  that  of  1890. 

Next  came  the  discovery  of  Eocene  material  from  the 
vicinity  of  Fort  Bridger,  Wyoming,  geologically  older 


VERTEBRATE  PALEONTOLOGY     231 

than  the  Nebraska  and  Dakota  formations.  This, 
together  with  specimens  from  the  Green  River  and 
Sweetwater  River  deposits  of  Wyoming  and  the  John 
Day  River  (Oligocene)  of  Oregon,  was  also  referred  to 
Leidy,  and  added  yet  more  to  the  list  of  newly  discov- 
ered species  with  which  he  had  already  become  familiar 
in  his  earlier  researches.  The  results  of  this  study  were 
published  by  the  Hayden  Survey  in  1873,  under  the  title 
**  Contributions  to  the  Extinct  Vertebrate  Fauna  of  the 
"Western  Territories. ''  This  was  the  last  of  Leidy 's 
major  works,  but  he  continued  up  to  the  time  of  his  death 
to  report  to  the  Academy  concerning  the  various  fossil 
forms  that  were  submitted  to  him  for  identification.  Of 
such  reports  the  most  important  was  one  on  the  fossils 
of  the  phosphate  beds  of  South  Carolina,  published  in 
the  Journal  of  the  Academy  in  1887. 

As  a  paleontologist,  Leidy  ranks  with  Cope  and 
Marsh  high  among  those  who  enriched  the  American  lit- 
erature of  the  subject,  but  it  must  be  remembered  that 
this  was  but  a  single  aspect  of  his  many-sided  scientific 
career,  for  he  made  many  contributions  of  high  order  to 
botany,  zoology,  and  general  and  comparative  anatomy 
as  well,  nor  did  his  knowledge  and  usefulness  as  an 
instructor  of  his  fellow  men  keep  within  the  limitations  of 
these  subjects. 

Othniel  Charles  Marsh  (1831-1899). 

The  sixth  decade  of  the  nineteenth  century  saw  the 
beginning  of  the  labors  of  several  paleontologists  who, 
like  Leidy,  were  destined  to  raise  the  science  of  fossil 
vertebrates  in  America  to  the  level  of  attainment  of  the 
Old  World.  They  were,  among  others,  Othniel  Charles 
Marsh  and  Edward  Drinker  Cope.  Of  these  the  names 
of  Marsh  and  Cope  are  linked  together  by  the  brilliance 
of  their  attainments,  their  contemporaneity,  and  the 
rivalry  which  the  similarity  of  their  pursuits  unfortu- 
nately engendered.  Marsh  produced  his  first  paleon- 
tological  paper  in  1862  (33,  278),  Cope  in  1864,  but  the 
latter  died  first,  so  that  his  life  of  research  was  shorter. 

To  Professor  Marsh  should  be  given  credit  for  the 
first  organized  expedition  designed  exclusively  for  the 
collection  of  vertebrate  remains,  the  results  of  which  con- 


232  A  CENTURY  OF  SCIENCE 

tain  so  much  material  that  it  has  not  yet  entirely  seen 
the  light  of  scientific  exposition.  Marsh's  first  trip  to 
the  West  was  in  1868,  the  first  formal  expedition  being 
organized  two  years  later.  These  expeditions,  of  which 
there  were  four,  were  privately  financed  except  for  the 
material  and  military  escort  furnished  by  the  United 
States  Government,  and  consisted  of  a  personnel  drawn 
entirely  from  the  graduate  or  undergraduate  body 
of  Yale  University.  These  parties  explored  Kansas, 
Nebraska,  Wyoming,  Utah,  and  Oregon,  and  returned 
laden  with  material  from  the  Cretaceous  and  Tertiary 
formations  of  the  West.  Some  of  this  is  of  necessity 
somewhat  fragmentary,  but  type  after  type  was  secured 
which,  with  his  exhaustive  knowledge  of  comparative 
anatomy,  enabled  Marsh  to  announce  discovery  after  dis- 
covery of  species,  genera,  families,  and  even  orders  of 
mammals,  birds,  and  reptiles  which  were  unknown  to 
science.  The  year  1873  saw  the  last  of  the  student  expe- 
ditions, and  thereafter  until  the  close  of  his  life  the  work 
of  collecting  was  done  under  Marsh's  supervision,  but  by 
paid  explorers,  many  of  whom  had  been  his  scouts  and 
guides  in  the  formal  expeditions  or  had  been  especially 
trained  by  him  in  the  East.  In  1882,  after  fourteen  years 
of  the  experience  thus  gained.  Marsh  was  appointed  verte- 
brate paleontologist  to  the  United  States  Geological  Sur- 
vey, which  relieved  him  in  part  of  the  personal  expense 
connected  with  the  collecting,  although  up  to  within 
a  short  time  of  his  death  his  own  fortune  was  very 
largely  spent  in  enlarging  his  collections.  After  his  con- 
nection with  the  Survey  was  established,  Marsh  had  two 
main  purposes  in  view  in  making  the  collections :  (1)  to 
determine  the  geological  horizon  of  each  locality  where 
a  large  series  of  vertebrate  fossils  was  found,  and  (2)  to 
secure  from  these  localities  large  collections  of  the  more 
important  forms  sufficiently  extensive  to  reveal,  if  possi- 
ble, the  life  histories  of  each.  Marsh  believed  that  the 
material  thus  secured  would  serve  as  key  or  diagnostic 
fossils  to  all  horizons  of  our  western  geology  above  the 
Paleozoic,  a  belief  in  which  he  was  in  advance  of  his  time, 
for  few  of  his  contemporaries  appreciated  the  value  of 
vertebrates  as  horizon  markers.  The  result  of  the  ful- 
filment of  his  second  purpose  saw  the  accumulation  of 


VERTEBRATE  PALEONTOLOGY     233 

huge  collections  from  all  horizons  above  the  Triassic  and 
some  Paleozoic  and  Triassic  as  well.  These  contained 
some  very  remarkable  series,  each  of  which  Marsh  hoped 
to  make  the  basis  of  an  elaborate  monograph  to  be  pub- 
lished under  the  auspices  of  the  Survey.  One  can  vis- 
ualize the  scope  of  his  ambitions  by  the  fact  that  no  fewer 
than  twenty-seven  projected  quarto  volumes,  to  contain 
at  least  850  lithographic  plates,  were  listed  by  him  in 
1877.  These  covered,  among  other  groups,  the  toothed 
birds  (Odontornithes),  Dinocerata,  horses,  brontotheres, 
pterodactyls,  mosasaurs  and  plesiosaurs,  monkeys,  car- 
nivores, perissodactyls  and  artiodactyls,  crocodiles, 
lizards,  dinosaurs,  various  birds,  proboscideans,  eden- 
tates and  marsupials,  brain  evolution,  and  the  Connecti- 
cut Valley  footprints.  Much  was  done  towards  the  prep- 
aration of  these  memoirs,  as  evidenced  by  the  long  list 
of  preliminary  papers,  admirably  illustrated  by  woodcuts 
which  were  to  form  the  text  figures  of  the  memoirs, 
which  appeared  with  great  regularity  in  the  pages  of  the 
Journal  for  a  period  of  thirty  years.  Of  the  actual 
memoirs,  however,  but  two  had  been  published  at  the 
time  of  Marsh's  death  in  1899 — the  Odontornithes  in 
1880  and  the  Dinocerata  in  1884.  One  must  not  overlook, 
however,  the  epoch-making  Dinosaurs  of  North  America, 
which  was  published  by  the  Survey  in  1896,  although  it 
was  not  in  the  form  nor  had  it  the  scope  of  the  proposed 
monographs.  This  was  not  due  to  lack  of  application, 
for  Professor  Marsh  was  an  indefatigable  worker,  but 
rather  to  the  fact  that  the  program  was  of  such  magni- 
tude as  to  necessitate  a  patriarchal  life  span  for  its  con- 
summation. As  it  is.  Professor  Marsh's  fame  rests  first 
upon  his  ability  and  intrepidity  as  a  collector,  ready  him- 
self to  brave  the  very  certain  hardships  and  dangers 
which  beset  the  field  paleontologist  in  the  pioneer  days, 
and  also  by  his  judgment  and  command  of  men  to  secure 
the  very  adequate  services  of  others  and  so  to  direct 
their  endeavors  that  the  results  were  of  the  highest  value. 
The  material  witness  to  Marsh's  skill  as  a  collector  lies 
in  the  collections  of  the  Peabody  Museum  at  Yale  and  in 
the  Marsh  collection  at  the  United  States  National 
Museum,  the  latter  secured  through  the  funds  of  the 
United  States  Geological  Survey.     Together  they  consti- 


234  A  CENTUEY  OF  SCIENCE 

tute  what  is  possibly  the  greatest  collection  of  fossil 
vertebrates  in  America,  if  not  in  the  world ;  individually, 
they  are  second  only  to  that  of  the  American  Museum  in 
New  York  City,  the  result  of  the  combined  labors  of 
Osborn  and  Cope  and  their  very  able  corps  of  assistants. 

As  a  scientist  Marsh  possessed  in  large  measure  that 
wide  knowledge  of  comparative  anatomy  so  necessary  to 
the  vertebrate  paleontologist,  and  as  a  consequence  was 
not  only  able  to  recognize  affinities  and  classify  unerr- 
ingly, but  also  to  recognize  the  salient  diagnostic  fea- 
tures of  the  form  before  him  and  in  few  words  so  to 
describe  them  as  to  render  the  recognition  of  the  species 
by  another  worker  relatively  easy.  The  publication  of 
hundreds  of  these  specific  diagnoses  in  the  Journal  con- 
stitutes a  very  large  and  valuable  part  of  that  periodi- 
cal's contribution  to  the  advancement  of  our  science. 
Marsh's  method  of  indicating  forms  by  so  brief  a  state- 
ment leaves  much  to  be  done,  however,  in  the  way  of 
further  description  of  his  types,  which  in  many  instances 
were  but  partially  prepared. 

Yet  another  important  service  which  Marsh  rendered 
to  science  was  the  restoration  of  the  creatures  as  a  whole, 
made  with  the  most  painstaking  care  and  precision 
through  assembling  the  drawings  of  the  individual  bones. 
These  restorations  have  become  classic,  embracing  as  they 
did  a  score  or  more  of  forms,  of  beast,  bird,  and  reptile. 
They  also  were  published  first  in  the  Journal,  although 
they  have  subsequently  been  reproduced  in  text-books 
and  other  works  the  world  over.  Part  of  Marsh's  popu- 
lar reputation,  at  least,  which  was  second  to  that  of  no 
other  American  in  his  line,  was  due  to  his  skill  in 
attaining  publicity,  for  his  papers,  of  whatever  extent, 
were  carefully  and  methodically  sent  to  correspondents 
in  the  uttermost  parts  of  the  earth,  and  thus  the  Marsh 
collection  has  reflected  the  fame  of  its  maker. 


Edward  DrinJcer  Cope  (1840-1897). 

The  third  great  name  in  American  vertebrate  paleon- 
tology, that  of  Edward  Drinker  Cope,  stands  out  in  sharp 
contrast  with  the  other  two,  although  in  the  range  of  his 
interests  he  was  probably  more  nearly  comparable  with 


VERTEBRATE  PALEONTOLOGY     235 

Leidy  than  with  Marsh.  The  beginning  of  Cope's  scien- 
tific labors  dates  from  1859,  the  year  made  famous  in  the 
annals  of  science  by  the  appearance  of  Darwin's  Origin 
of  Species.  It  is  not  surprising,  therefore,  that  matters 
evolutional  should  have  interested  him  to  the  very  end  of 
his  career.  Cope  was  not  merely  a  paleontologist,  but  was 
interested  in  recent  forms,  especially  the  three  lower 
classes  of  vertebrates,  to  such  an  extent  that  his  work 
therewith  is  highly  authoritative  and  in  some  respects 
epoch-making.  Thirty-eight  years  of  almost  continual 
toil  were  his,  and  the  mere  mass  of  his  literary  productions 
is  prodigious,  especially  when  one  realizes  that,  unlike 
those  of  a  writer  of  fiction,  they  were  based  on  painstaking 
research  and  philosophical  thought.  The  greater  part  of 
Cope's  life  was  spent  in  or  near  Philadelphia  except  for 
his  western  explorations,  and  he  is  best  known  as  pro- 
fessor of  geology  and  paleontology  in  the  University  of 
Pennsylvania,  although  he  served  other  institutions  as 
well. 

Cope's  early  work  was  among  the  amphibia  and  rep- 
tiles, his  first  paleontological  paper,  the  description  of 
Amphihamus  grandiceps,  appearing  in  1865.  This  year 
he  also  began  his  studies  of  the  mammals,  especially  the 
Cetacea,  both  living  and  extinct,  from  the  Atlantic  sea- 
board. The  next  year  saw  the  beginning  of  his  work  on 
the  material  from  the  Cretaceous  marls  of  New  Jersey, 
describing  therefrom  one  of  the  first  carnivorous  dino- 
saurs, Lcelaps,  to  be  discovered  in  America.  In  1868 
Cope  began  to  describe  the  vertebrates  from  the  Kansas 
chalk  and  three  years  later  made  his  first  exploration  of 
these  beds.  This  led  to  his  connection  with  the  United 
States  Geological  Survey  of  the  Territories  under  Hay- 
den,  and  to  continued  exploration  of  Wyoming  and  Col- 
orado in  1872  and  1873.  The  material  thus  gained, 
consisting  of  fishes,  mosasaurs,  dinosaurs,  and  other 
reptiles,  was  described  in  the  Transactions  of  the 
American  Philosophical  Society  as  well  as  in  the  Survey 
Bulletins.  In  1875  these  results  were  summarized  in  a 
large  quarto  volume  entitled  ^^Vertebrata  of  the  Creta- 
ceous formations  of  the  West."  Subsequent  summers 
were  spent  in  further  exploration  of  the  Bridger,  Washa- 
kie, and  Wasatch  formations  of  Wyoming,  the  Puerco 


236  A  CENTURY  OF  SCIENCE 

and  Torrejon  of  New  Mexico,  and  the  Judith  River  of 
Montana.  The  material  gathered  in  New  Mexico  proved 
particularly  valuable,  and  led  to  the  publication  in  1877 
of  another  notable  volume  entitled  *^  Report  upon  the 
Extinct  Vertebrata  obtained  in  New  Mexico  by  Parties 
of  the  Expedition  of  1874.'' 

Material  was  now  accumulating  so  fast  as  to  necessi- 
tate the  concentration  of  Cope's  own  time  on  research, 
so  that,  while  he  continued  to  make  brief  journeys  to  the 
West,  the  real  work  of  exploration  was  delegated  to 
Charles  H.  Sternberg  and  J.  L.  Wortman,  both  of  whom 
became  subsequently  very  well  known,  the  former  as  a 
collector  whose  active  service  has  not  yet  ceased,  the 
latter  as  an  explorer  and  later  an  investigator  of 
extremely  high  promise. 

As  early  as  1865,  Cope  began  no  fewer  than  five  sep- 
arate lines  of  research  which  he  pursued  concurrently 
for  the  remainder  of  his  career.  On  the  fishes,  he  became 
a  high  authority  in  the  larger  classification,  owing  to  his 
researches  into  their  phylogeny,  for  which  a  knowledge 
of  extinct  forms  is  imperative.  On  amphibia,  he  wrote 
more  voluminously  than  any  other  naturalist,  discussing 
not  only  the  morphology  but  the  paleontology  and  tax- 
onomy as  well.  In  this  connection  must  be  mentioned 
not  only  Cope's  exploration  and  collections  in  the  Per- 
mian of  Ohio  and  Illinois,  but  especially  the  remains 
from  the  Texas  Permian,  first  received  in  1877,  upon 
which  some  of  his  most  brilliant  results  were  based; 
these  of  course  included  reptilian  as  well  as  amphibian 
material.  His  third  line  of  research,  the  Reptilia,  is  in 
part  included  in  the  foregoing,  but  also  embraced  the 
reptiles  of  the  Bridger  and  other  Tertiary  deposits,  those 
of  the  Kansas  Cretaceous,  and  the  Cretaceous  dinosaurs. 

Up  to  1868  Leidy  alone  was  engaged  in  research  in  the 
AVest,  but  that  year  saw  the  simultaneous  entrance  of 
Marsh  and  Cope  into  this  new  field  of  research,  and  their 
exploration  and  descriptions  of  similar  regions  and  forms 
soon  led  to  a  rivalry  which  in  turn  developed  into  a  most 
unfortunate  series  of  controversies,  mainly  over  the  sub- 
ject of  priority.  This  resulted  in  a  permanent  rupture 
of  friendship  and  the  division  of  American  workers  into 
two  opposing  camps  to  the  detriment  of  the  progress  of 


VERTEBRATE  PALEONTOLOGY     237 

our  science.  This  breach  has  now  been  happily  healed, 
and  for  a  number  of  years  the  degree  of  mutual  good  will 
and  aid  on  the  part  of  our  workers  has  been  of  the  high- 
est sort. 

The  extent  of  the  western  fossil  area,  and  particularly 
the  explorations  of  three  of  Cope's  aids,  Wortman  in  the 
Big  Horn  and  Wasatch  basins,  Baldwin  in  the  Puerco  of 
New  Mexico,  and  Cummins  in  the  Permian  of  Texas,  gave 
him  so  fruitful  a  field  of  endeavor  that  the  occasion  for 
jealous  rivalry  was  largely  removed.  The  most  manifest 
result  of  Cope's  western  work  was  the  publication  in 
1883  of  his  Vertebrata  of  the  Tertiary  Formations  of  the 
West,  which  formed  volume  3  of  the  quarto  publications 
of  the  Hayden  Survey.  This  huge  book  contains  more 
than  1000  pages  and  80  plates  and  has  been  facetiously 
called  ** Cope's  Bible.'' 

Cope's  philosophical  contributions,  which  covered  the 
domains  of  evolution,  psychology,  ethics,  and  meta- 
physics, began  in  1868  with  his  paper  on  The  Origin  of 
Genera.  In  evolution  he  was  a  follower  of  Lamarck,  and 
as  such,  with  Hyatt,  Ryder,  and  Packard,  was  one  of  the 
founders  of  the  so-called  Neo-Lamarckian  School  in 
America.  Cope 's  principal  contribution,  set  forth  in  his 
Factors  of  Organic  Evolution,  is  the  idea  of  kinetogenesis 
or  mechanical  genesis,  the  principle  that  all  structures 
are  the  direct  outcome  of  the  stresses  and  strains  to 
which  the  organism  is  subjected.  Weismann's  forcible 
attack  on  the  transmission  theory  did  not  shake  Cope's 
faith  in  these  doctrines,  for  he  claimed  that  the  paleon- 
tological  evidence  for  the  inheritance  of  such  characters 
as  are  apparently  the  result  of  individual  modification 
was  too  strong  to  be  refuted.  Cope  was  more  like 
Lamarck  than  any  other  naturalist  in  his  mental  make-up 
as  well  as  his  ideas.  He  was  also,  like  Haeckel,  given 
to  working  out  the  phylogeny  of  whatever  type  lay  before 
him,  and  in  many  instances  arrived  marvellously  near  the 
truth  as  we  now  see  it. 

Associated  for  a  while  with  A.  S.  Packard,  Cope  soon 
became  chief  editor  and  proprietor  of  the  American  Nat- 
uralist, which  was  for  many  years  his  main  means  of  pub- 
lication and  thus  served  our  science  in  a  way  comparable 
to  the  Journal.    As  Osborn  says  by  way  of  summation: 

15 


238  A  CENTURY  OF  SCIENCE 

'  *  Cope  is  not  to  be  thought  of  merely  as  a  specialist  in  Paleon- 
tology. After  Huxley  he  was  the  last  representative  of  the  old 
broad-gauge  school  of  anatomists  and  is  only  to  be  compared 
with  members  of  that  school.  His  life-work  bears  marks  of  great 
genius,  of  solid  and  accurate  observation,  and  at  times  of  inac- 
curacy due  to  bad  logic  or  haste  and  overpressure  of  work. 
.  .  .  As  a  comparative  anatomist  he  ranks  both  in  the  range 
and  effectiveness  of  his  knowledge  and  his  ideas  with  Cuvier  and 
Owen.  .  .  .  As  a  natural  philosopher,  while  far  less  logical 
than  Huxley,  he  was  more  creative  and  constructive,  his  meta- 
physics ending  in  theism  rather  than  agnosticism." 

1870-1880. 

The  seventh  decade  was  productive  of  comparatively 
few  great  names  in  the  history  of  our  science,  but  two, 
J.  A.  Ryder  and  Samuel  W.  Williston,  being  notable  con- 
tributors. The  former  produced  but  few  papers  and 
those  between  1877  and  1892,  yet  they  were  of  note  and 
such  was  their  influence  that  he  is  named  with  Hyatt, 
Packard,  and  Cope  as  one  of  the  founders  of  the  Neo- 
Lamarckian  School  of  evolutionists  in  America.  Ryder 
was  a  particular  friend  and  a  colleague  of  Cope,  as  they 
were  both  concerned  with  the  back-boned  animals,  while 
the  other  two  were  invertebratists.  Ryder  wrote  on 
mechanical  genesis  of  tooth  forms  and  on  scales  of  fishes, 
also  on  the  morphology  and  evolution  of  the  tails  of 
fishes,  cetaceans,  and  sirenians,  and  of  the  other  fins  of 
aquatic  types.  He  did,  on  the  other  hand,  practically  no 
systematic  or  descriptive  work. 

Williston,  on  the  contrary,  has  had  a  long  and  varied 
career  as  an  investigator  and  as  an  educator.  Trained 
at  Yale,  he  prepared  for  medicine,  and  much  of  his  teach- 
ing has  been  of  human  anatomy,  both  at  Yale  and  at  the 
University  of  Kansas  where  he  served  for  a  number  of 
years  as  dean  of  the  Medical  School.  He  is  also  a  stu- 
dent of  flies,  and  as  such  not  only  the  foremost  but  indeed 
almost  the  only  dipterologist  in  the  United  States.  But 
it  is  with  his  work  as  a  vertebrate  paleontologist  that  we 
are  chiefly  concerned,  and  here  again  he  stands  among 
the  foremost.  His  initial  work  and  training  in  this 
department  of  science  were  with  Marsh,  for  whom  he 
spent  many  months  in  field  work,  collecting  largely  in  the 
Niobrara  Cretaceous  of  Kansas.     He  did,  however,  no 


VERTEBRATE  PALEONTOLOGY     239 

research  while  with  Marsh,  owing  to  the  latter 's  disin- 
clination to  foster  such  work  on  the  part  of  his  associates. 
Williston  began  his  publications  in  1878  and  has  con- 
tinued them  until  the  present,  working  mainly  with  Cre- 
taceous mosasaurs,  plesiosaurs,  and  pterodactyls.  Of 
late,  since  his  transference  to  the  University  of  Chicago, 
where  as  professor  of  paleontology  and  director  of  the 
"Walker  Museum  he  has  served  since  1902,  his  interest  has 
lain  mainly  among  the  Paleozoic  reptiles  and  amphibia. 
Williston 's  more  notable  works  are  American  Permian 
Vertebrates  and  Water  Reptiles  of  the  Past  and  Present, 
wherein  he  sets  forth  his  views  of  the  phylogenesis  and 
taxonomy  of  the  reptilian  class.  He  is  at  present  at 
work  on  the  evolution  of  the  reptiles,  a  volume  which  is 
eagerly  awaited  by  his  colleagues.  It  is  in  morphology 
that  Williston 's  greatest  strength  lies  and  some  of 
his  most  effective  work  on  the  mosasaurs  has  appeared 
in  the  Journal. 

1880-1900. 

The  next  decade,  that  of  1880-1890,  saw  a  number  of 
notable  additions  to  the  workers  in  vertebrate  paleontol- 
ogy:  Henry  F.  Osborn,  W.  B.  Scott,  R.  W.  Shufeldt,  J.  L. 
Wortman,  George  Baur,  F.  A.  Lucas,  and  F.  W.  True. 
Shufeldt  is  our  highest  authority  on  the  osteology  of 
birds,  both  recent  and  extinct,  having  recently  described 
all  of  the  extinct  forms  contained  in  the  Marsh  collec- 
tion ;  True  wrote  of  Cetacea ;  Lucas  of  marine  and  Pleis- 
tocene mammals  and  birds,  and  has  also  written  popular 
books  on  prehistoric  life.  Lucas 's  greatest  service,  how- 
ever, lies  in  the  museums,  where  he  has  manifested  a 
genius  second  to  none  in  the  installation  of  mute  evi- 
dences of  living  and  past  organisms.  Wortman  was  for 
a  time  associated  with  Cope,  later  with  Osborn  in  the 
American  Museum,  again  at  the  Carnegie  Museum  at 
Pittsburgh,  and  finally  at  Yale  in  research  on  the  Bridger 
Eocene  portion  of  the  Marsh  collection.  His  work  has 
been  chiefly  the  perfection  of  field  methods  ill  vertebrate 
paleontology,  and  as  a  special  investigator  of  Tertiary 
Mammalia,  treating  the  latter  largely  from  the  morpho- 
logic and  taxonomic  standpoints.  Wortman 's  Yale 
results  on  the  carnivores  and  primates  of  the  Eocene, 


240  A  CENTURY  OF  SCIENCE 

as  yet  unfinished,  were  published  in  the  Journal  in 
1901-1904. 

"William  B.  Scott  is  a  graduate  of  Princeton,  and  has 
spent  thirty-four  years  in  her  service  as  Blair  Professor 
of  Geology  and  Paleontology.  His  first  publication,  in 
1878,  issued  in  conjunction  with  Osborn  and  Speir, 
described  material  collected  by  them  in  the  Eocene  for- 
mations of  the  West,  and  since  that  time  Scott's  research 
has  been  entirely  with  the  mammals,  on  which  he  is  one  of 
our  highest  authorities.  His  most  notable  works  have 
been  a  History  of  Land  Mammals  of  the  Western  Hemi- 
sphere, 1913,  and  the  results  of  the  Patagonian  expedi- 
tions by  Hatcher,  which  are  published  in  a  quarto  series 
in  conjunction  with  W.  J.  Sinclair,  although  they  are  the 
authors  of  separate  volumes,  Scott's  work  being  mainly 
on  the  carnivores  and  edentates  of  the  Santa  Cruz  forma- 
tion. It  is  as  a  systematist  in  research  and  as  an  educa- 
tor that  Scott  has  attained  his  highest  usefulness. 

The  man  who,  next  to  the  three  pioneers,  has  attained 
the  highest  reputation  in  vertebrate  paleontologio 
research,  is  Henry  Fairfield  Osborn.  Graduate  of 
Princeton  in  the  same  class  that  produced  Scott,  Osborn 
served  for  a  time  as  professor  of  comparative  anatomy 
in  that  institution,  and  in  1891  was  called  to  New  York  to 
organize  the  department  of  zoology  in  Columbia  Uni- 
versity and  that  of  vertebrate  paleontology  in  the  Ameri- 
can Museum  of  Natural  History.  He  had,  early  in  his 
career,  gone  west  in  company  with  Professor  Scott,  and 
had  collected  material  from  the  Eocene  formation  of 
Wyoming,  upon  which  they  based  their  first  joint  paper 
in  1878,  Osborn 's  first  independent  production,  a  memoir 
on  two  genera  of  Dinocerata,  appearing  in  1881.  A  num- 
ber of  papers  followed,  on  the  Mesozoic  Mammalia,  on 
Cope's  tritubercular  theory,  and  on  certain  apparent  evi- 
dences for  the  transmission  of  acquired  characters.  It 
was,  however,  with  his  acceptance  of  the  New  York 
responsibilities,  especially  at  the  American  Museum, 
that  Osborn 's  most  significant  work  began.  Aided  first 
by  Wortman  and  Earle,  later  by  W.  D.  Matthew  and 
others,  he  has  built  up  the  greatest  and  most  complete 
collection  of  fossil  vertebrates  extant;  its  value,  how- 
ever, was  largely  enhanced  through  the  purchase  of  the 


VERTEBRATE  PALEONTOLOGY     241 

private  collection  of  Professor  Cope,  which  of  course 
included  a  large  number  of  types.  The  American 
Museum  collection  thus  contains  not  only  a  vast  series 
of  representative  specimens  from  every  class  and  order 
of  vertebrates,  secured  by  purchase  or  expedition  from 
nearly  all  the  great  localities  of  the  world,  but  an  exhi- 
bition series  of  skulls  and  partial  and  entire  skeletons 
and  restorations  which  no  other  institution  can  hope  to 
equal.  Based  upon  this  wonderful  material  is  a  large 
amount  of  research,  filling  many  volumes,  published  for 
the  greater  part  in  the  bulletin  and  memoirs  of  the 
Museum.  This  research  is  not  only  the  product  of  the 
staff,  including  Walter  Granger,  Barnum  Brown,  W.  D. 
Matthew,  and  W.  K.  Gregory,  but  also  of  a  number  of 
other  American  and  some  foreign  paleontologists  as  well. 

Professor  Osborn's  OAvn  work  has  been  voluminous,  his 
bibliography  from  1877  to  1916  containing  no  fewer  than 
441  titles,  ranging  over  the  fields  of  paleontology, — which 
of  course  includes  the  greater  number — geology,  correla- 
tion and  paleogeography,  evolutionary  principles  exem- 
plified in  the  Mammalia,  man,  neurology  and  embry- 
ology, biographies,  and  the  theory  of  education. 

In  paleontology,  Osborn's  researches  have  been  largely 
with  the  Reptilia  and  Mammalia,  partly  morphological, 
but  also  taxonomic  and  evolutional.  Faunistic  studies 
have  also  been  made  of  the  mammals.  Of  his  published 
volumes  the  most  important  are,  first,  the  Age  of  Mam- 
mals (1910),  in  which  he  treats  not  of  evolutionary  series 
of  phylogenies,  but  of  faunas  and  their  origin,  migra- 
tions, and  extinctions,  and  of  the  correlation  of  Old  and 
New  World  Tertiary  deposits  and  their  contents.  Men 
of  the  Old  Stone  Age  (1916)  is  an  exhaustive  treatise  and 
is  the  first  full  and  authoritative  American  presentation 
of  what  has  been  discovered  up  to  the  present  time 
throughout  the  world  in  regard  to  human  prehistory.  In 
his  latest  volume.  The  Origin  and  Evolution  of  Life 
(1917),  Osborn  presents  a  new  energy  conception  of  evo- 
lution and  heredity  as  against  the  prevailing  matter  and 
form  conceptions.  In  this  volume  there  is  summed  up 
the  whole  story  of  the  origin  and  evolution  of  life  on 
earth  up  to  the  appearance  of  man.  This  last  book  is 
novel  in  its  conceptions,  but  it  is  too  early  as  yet  to  judge 


242  A  CENTURY  OF  SCIENCE 

of  the  acceptance  of  Osborn's  theses  by  his  fellow  work- 
ers in  science. 

Since  the  death  of  Professor  Marsh,  Osborn  has  served 
as  vertebrate  paleontologist  to  the  United  States  Geolog- 
ical Survey,  and  has  in  charge  the  carrying  through  to 
completion  of  the  many  monographs  proposed  by  his  dis- 
tinguished predecessor.  One  of  these,  that  on  the  horned 
dinosaurs,  has  been  completed  by  Hatcher  and  Lull 
(1907),  another  on  the  stegosaurian  dinosaurs  has  been 
carried  forward  by  C.  W.  Gilmore  of  the  United  States 
National  Museum,  while  under  Osborn 's  own  hand  are 
the  memoirs  on  the  titanotheres  (aided  by  W.  K.  Greg- 
ory), the  horses,  and  the  sauropod  dinosaurs.  Of  these, 
the  first,  when  it  shall  have  been  completed,  promises  to 
be  the  most  monumental  and  exhaustive  study  of  a  group 
of  fossil  organisms  ever  undertaken. 

As  a  leader  in  science,  a  teacher  and  administrator, 
Professor  Osborn 's  rank  is  high  among  the  leading  verte- 
bratists.  He  is  remarkably  successful  in  his  choice  of 
assistants  and  in  stimulating  them  in  their  productive- 
ness so  that  their  combined  results  form  a  very  consider- 
able share  of  the  later  literature  in  America. 

The  ninth  decade  ushered  in  the  work  of  a  valuable 
group  of  students,  of  whom  John  Bell  Hatcher  should  be 
mentioned  in  particular,  as  his  work  is  done.  Graduate 
of  Yale  in  1884,  he  spent  a  number  of  years  assisting 
his  teacher.  Professor  Marsh,  mainly  in  the  field,  collect- 
ing during  that  time,  either  for  Yale  or  for  the  United 
States  Geological  Survey,  an  enormous  amount  of  very 
fine  material,  especially  from  the  West,  although  he  also 
collected  in  the  older  Tertiary  and  Potomac  beds  near 
Washington.  In  the  West  he  secured  no  fewer  than 
105  titanothere  skulls,  explored  the  Tertiary,  Judith 
River,  and  Lance  formations,  collected  and  in  fact  vir- 
tually discovered  the  remains  of  the  Cretaceous  mammals 
and  of  the  horned  dinosaurs  which  he  was  later  privileged 
to  describe.  He  then  (1893)  went  to  Princeton,  which  he 
served  for  seven  years,  his  principal  work  being  explora- 
tions in  Patagonia  for  the  E.  and  M.  Museum,  one  direct 
result  of  which  was  the  publication  of  a  large  quarto  on 
the  narrative  of  the  expedition  and  the  geography  and 
ethnography    of    the    region.     Going    to    the    Carnegie 


VERTEBRATE  PALEONTOLOGY     243 

Museum  in  Pittsburgh  in  1900,  Hatcher  carried  forward 
the  work  of  exploration  and  collecting  begun  for  that 
institution  by  Wortman,  and  as  a  partial  result  prepared 
many  papers,  the  principal  ones  being  memoirs  on  the 
dinosaurs  Haplocanthosaurus  and  Diplodocus.  In  1903, 
with  T.  W.  Stanton  of  the  United  States  Geological  Sur- 
vey, Hatcher  explored  the  Judith  River  beds  and  together 
they  settled  the  vexatious  problem  of  their  age,  the 
published  results  appearing  in  1905,  after  Hatcher's 
death.  His  last  piece  of  research,  begun  in  1902  and 
continued  until  his  death  in  1904,  was  an  elaborate  mono- 
graph on  the  Ceratopsia,  one  of  the  many  projected  by 
Marsh.  Of  this  memoir  Hatcher  had  completed  some 
150  printed  quarto  pages,  giving  a  rare  insight  into  the 
anatomy  of  these  strange  forms.  The  final  chapters, 
however,  which  were  based  very  largely  upon  Hatcher's 
own  opinions,  had  to  be  prepared  by  another  hand. 

Despite  his  early  death,  therefore,  Hatcher  rendered 
a  very  signal  service  to  American  paleontology — in 
exploration,  stratigraphy,  morphology,  and  systematic 
revision — and  his  activity  in  planning  new  fields  of 
research,  such,  for  instance,  as  the  exploration  of  the 
Antarctic  continent,  gave  promise  of  further  high  attain- 
ment, when  his  hand  was  arrested  by  death. 

Summary, 

It  is  not  surprising  that  American  vertebrate  paleontol- 
ogy has  arisen  to  so  high  a  plane,  when  one  considers  the 
material  at  its  disposal.  Having  a  vast  and  virgin  field 
for  exploration,  a  sufficient  number  of  collectors,  some  of 
whom  have  devoted  much  of  their  lives  to  the  work,  and 
a  refinement  of  technique  that  permitted  the  preservation 
of  the  fragmental  and  ill  conserved  as  well  as  the  finer 
specimens,  the  results  could  hardly  have  been  otherwise. 
Thus  it  has  been  possible  to  secure  material  almost 
unique  throughout  the  world  for  extent,  for  complete- 
ness, and  for  variety.  To  this  must  be  added  a  certain 
American  daring  in  the  matter  of  the  restoration  of  miss- 
ing portions,  both  of  the  individual  bones  and  of  the 
skeleton  as  a  whole,  such  as  European  conservatism  will 
not  as  a  rule  permit.  This  work  has  for  the  most  part 
been  done  after  the  most  painstaking  comparison  and 


244  A  CENTURY  OF  SCIENCE 

researcli  and  is  highly  justified  in  the  accuracy  of  the 
results,  which  render  the  fabric  of  the  skeleton  much 
more  intelligible,  both  to  the  scientist  and  to  the  layman. 
Material  once  secured  and  prepared  is  then  mounted, 
and  here  again  American  ingenuity  has  accomplished 
some  remarkable  results.  Some  of  the  specimens  thus 
mounted  are  so  small  and  delicate  as  to  require  holding 
devices  comparable  to  those  for  the  display  of  jewels; 
yet  others — huge  dinosaurs  the  bones  of  which  are  enor- 
mously heavy,  but  so  brittle  that  they  will  not  bear  even 
the  weight  of  a  process  unsupported — require  a  care- 
fully designed  and  skilfully  worked  out  series  of  supports 
of  steel  or  iron  which  must  be  perfectly  secure  and  at  the 
same  time  as  inconspicuous  as  possible.  And  of  late  the 
lifelike  pose  of  the  individual  skeleton  has  been  aug- 
mented by  the  preparation  of  groups  of  several  animals 
which  collectively  exhibit  sex,  size,  or  other  individual 
variations  and  the  full  mechanics  of  the  skeleton  under 
the  varying  poses  assumed  by  the  creature  during  life. 

The  work  of  further  restoration  has  been  rendered  pos- 
sible through  comparative  anatomical  study,  enabling  us 
to  essay  restorations  in  entirety  by  means  of  models  and 
drawings,  clothing  the  bones  with  sinews  and  with  flesh 
and  the  flesh  with  skin  and  hair,  if  such  the  creature 
bore ;  while  the  laws  of  f aunal  coloration  have  permitted 
the  coloring  of  the  restoration  in  a  way  which  if  not  the 
actual  hue  of  life  is  a  very  reasonable  possibility. 

Thus  the  American  paleontologists  have  blazed  a  trail 
which  has  been  followed  to  good  effect  by  certain  of  their 
Old  World  colleagues. 

With  such  means  and  methods  and  such  material  avail- 
able, it  is  again  not  surprising  that  American  paleontology 
has  furnished  more  and  more  of  the  evidences  of  evolu- 
tion, and  disclosed  to  the  eyes  of  scientists  animal  rela- 
tionships which  were  undreamed  of  by  the  systematist 
whose  research  dealt  only  with  the  existing.  It  has  also 
explained  some  vexatious  problems  of  animal  distribution 
and  of  extinction,  and  has  connected  up  cause  and  effect 
in  the  great  evolutionary  movements  which  are  recorded. 

The  results  of  systematic  research  have  added  hosts  of 
new  genera  and  species  and  of  families,  but  of  orders 
there    are    relatively     few.     Nevertheless     a    number. 


VERTEBRATE  PALEONTOLOGY     245 

especially  among  reptiles  and  mammals,  have  come  to 
light  as  the  fruits  of  American  discovery.  But  aside 
from  the  dry  cataloguing  of  such  groups,  the  American 
systematists  have  worked  out  some  very  remarkable  phy- 
logenies  and  have  thus  clarified  our  vision  of  animal 
relationships  in  a  way  which  the  recent  zoologist  could 
never  have  done.  In  this  connection,  the  Permian  ver- 
tebrates, which  have  been  collected  and  studied  with 
amazing  success,  principally  by  Williston  and  Case, 
should  be  mentioned,  although  the  work  is  yet  incom- 
plete. Some  of  these  forms  are  amphibian,  others  rep- 
tilian, yet  others  of  such  character  as  to  link  the  two 
classes  as  transitional  forms.  Of  the  Mesozoic  reptiles, 
a  very  remarkable  assemblage  has  come  to  light,  in  a 
degree  of  perfection  unknown  elsewhere.  These  are  dino- 
saurs, of  which  several  phyla  are  now  known;  carnivores 
both  great  and  small,  some  of  the  latter  being  actually 
toothless;  Sauropoda,  whose  perfection  and  dimensions 
are  incomparable  except  for  those  found  in  East  Africa ; 
and  predentates,  armored,  unarmored,  and  horned,  the 
last  exclusively  American.  The  unarmored  trachodonts 
are  now  known  in  their  entirety,  for  not  only  has  our 
West  produced  articulated  skeletons  but  mummified  car- 
casses whose  skin  and  other  portions  of  their  soft 
anatomy  are  represented,  and  which  are  thus  far  without 
a  parallel  elsewhere  in  the  world.  Other  reptilian 
groups  are  well  known,  notably  the  Triassic  ichthyosaurs, 
and  the  mosasaurs  and  plesiosaurs  of  the  Kansas  chalk. 
The  last  formation  has  also  produced  toothed  birds, 
Hesperornis  and  Ichthyornis,  which  again  are  absolutely 
unique. 

But  it  is  in  the  mammalian  class  that  the  phylogenies 
become  so  highly  complete  and  of  such  great  importance 
as  evolutionary  evidences,  for  nowhere  else  than  in  our 
own  West  have  such  series  been  found  as  the  Dinocerata 
and  creodonts  among  archaic  forms,  the  primitive 
primates  from  the  Eocene,  the  carnivores  such  as  the 
dogs  and  cats  and  mustellids,  but  especially  the  hoofed 
orders  such  as  the  horses.  Of  these  hoofed  orders,  the 
classic  American  series  of  horses  is  complete,  that  of 
the  camels  probably  no  less  so,  while  much  is  known  of 
the  deer  and  oreodonts,  the  last  showing  several  parallel 


246  A  CENTURY  OF  SCIENCE 

phyla,  and  of  the  proboscideans,  which  while  having  their 
pristine  home  in  the  Old  World  nevertheless  soon  sought 
the  new  where  their  remains  are  found  from  the  Miocene 
until  their  final  and  apparently  very  recent  extinction. 
These  creatures  show  increase  of  bulk,  perfection  of  feet 
and  teeth,  development  of  various  weapons,  horns  and 
antlers,  which  may  be  studied  in  their  relationship  with 
the  other  organs  to  make  the  evolving  whole,  or  their 
evolution  may  be  traced  as  individual  structures  which 
have  their  rise,  culmination,  and  sometimes  their  senile 
atrophy  in  a  way  comparable  to  that  of  the  representa- 
tives of  the  order  as  a  whole.  Thus,  for  example, 
Osborn  has  traced  the  evolution  of  the  molar  teeth,  and 
Cope  of  the  feet,  while  Marsh  has  shown  that  brain  devel- 
opment runs  a  similar  course  and  that  its  degree  of  per- 
fection within  a  group  is  a  potent  factor  for  survival. 
As  a  student  of  evolution,  the  paleontologist  sees 
things  in  a  very  different  light  from  the  zoologist.  The 
latter  is  concerned  largely  with  matters  of  detail — with 
the  inheritance  of  color  or  of  the  minor  and  more  super- 
ficial characteristics  of  animals — and  the  period  of 
observation  of  such  phenomena  is  of  necessity  brief 
because  of  the  mortality  of  the  observer.  Whereas  the 
paleontologist  has  a  perspective  which  the  other  lacks, 
since  for  him  time  means  little  in  the  terms  of  his  own 
life,  and  he  can  look  into  the  past  and  see  the  great  and 
fundamental  changes  which  evolution  has  wrought,  the 
rise  of  phyla,  of  classes,  of  orders,  and  he  alone  can  see 
the  orderliness  of  the  process  and  sense  the  majesty  of 
the  laws  which  govern  it. 

Influence  of  the  American  Journal  of  Science, 

The  influence  of  the  American  Journal  of  Science  as  a 
medium  for  the  dissemination  of  the  results  of  vertebrate 
research  has  been  in  evidence  throughout  this  discussion, 
but  it  were  well,  perhaps,  to  emphasize  that  service  more 
fully.  The  Journal  was,  as  we  have  seen,  the  chief  outlet 
for  Professor  Marsh's  research,  for  there  were  published 
in  it  during  his  lifetime  no  fewer  than  175  papers  descrip- 
tive of  the  forms  which  he  studied,  as  well  as  a  great  part 
of  the  material  in  the  published  monographs.     As  Marsh 


VERTEBRATE  PALEONTOLOGY     247 

left  very  few  manuscript  notes,  the  importance  of  these 
frequent  publications  in  thus  setting  forth  much  that  he 
thought  and  learned  concerning  the  material  is  very 
great  indeed.  The  combined  titles  of  all  other  authors  in 
the  Journal  in  this  line  of  research  for  the  century  of  its 
life  fall  far  short  of  the  number  produced  by  Marsh 
alone,  as  they  include  136  all  told,  but  the  range  of  sub- 
jects is  highly  representative  of  the  entire  field  of  verte- 
brate research.  It  should  be  borne  in  mind,  moreover, 
that  Leidy,  Cope,  and  Osborn  each  had  another  medium 
of  publication,  which  of  course  is  true  of  other  workers 
in  the  great  museums  such  as  the  American,  National, 
and  Carnegie,  all  of  which  issue  bulletins  and  quarto 
publications  for  the  purpose  of  disseminating  the  work 
of  their  staff.  Many  of  the  earlier  announcements  of  the 
discovery  of  vertebrate  relics  appeared  in  the  Journal,  as 
did  practically  all  the  literature  of  the  science  of  fossil 
footprints  (ichnology),  except  of  course  the  larger 
quartos  of  Hitchcock  and  Deane.  Of  the  footprint 
papers  by  Hitchcock,  Deane,  and  others,  there  were  no 
fewer  than  thirty-two,  with  a  number  of  additional  com- 
munications on  attendant  phenomena  bones  and  plants. 
Up  to  1847,  except  for  a  few  foreign  announcements, 
the  Journal  published  almost  exclusively  on  eastern  Amer- 
ican paleontology,  the  only  exception  being  a  notice  of 
bones  from  Oregon  by  Perkins  in  1842.  In  1847  came  the 
announcement  of  a  western  *  *  Palaeothere "  by  Prout, 
which  marked  the  beginning  of  the  researches  of  Leidy 
and  others  in  the  Bad  Lands  of  the  great  Nebraska 
plains.  The  Journal  thenceforth  published  paper  after 
paper  on  forms  from  all  over  North  America,  and  on  all 
aspects  of  our  science:  discovery,  systematic  descrip- 
tion, faunal  relationships,  evolutionary  evidences — thus 
showing  that  breadth  and  catholicity  which  has  made  it 
so  great  a  power  in  the  advancement  of  science. 


VII 

THE  RISE  OF  PETROLOGY  AS  A  SCIENCE 

By  LOUIS  V.  PIRSSON 

THIS  chapter  is  intended  to  present  a  brief  sketch  of 
the  progress  of  the  science  of  petrology  from  its 
early  beginnings  down  to  the  present  time.  The 
field  to  be  covered  is  so  large  that  this  can  be  done  only  in 
broadest  outline,  and  it  has  therefore  been  restricted  chiefly 
to  what  has  been  accomplished  in  America.  Although  the 
period  covered  by  the  life  of  the  Journal  extends  back- 
ward for  a  century  it  is,  however,  practically  only 
within  the  last  fifty  years  that  the  rocks  of  the  earth's 
crust  have  been  made  the  subject  of  such  systematic 
investigation  by  minute  and  delicately  accurate  methods 
of  research  as  to  give  rise  to  a  distinct  branch  of  geologic 
science.  It  is  not  intended  of  course  to  affirm  by  this 
statement  that  the  broader  features  of  the  rocks,  espe- 
cially those  which  may  be  observed  in  the  field  and  which 
concern  their  relations  as  geologic  masses,  had  not  been 
made  the  object  of  inquiry  before  this  time,  since  this  is 
the  very  foundation  of  geology  itself.  Moreover,  a  cer- 
tain amount  of  investigation  of  rocks,  as  to  the  minerals 
of  which  they  were  composed,  the  significance  of  their 
textures,  and  their  chemical  composition,  had  been  car- 
ried out,  concomitant  with  the  growth  from  early  times 
of  geology  and  mineralogy.  Thus,  in  1815,  Cordier  by  a 
process  of  washing  separated  the  components  of  a  basalt 
and  by  chemical  tests  determined  the  constituent  min- 
erals. At  the  time  the  Journal  was  founded,  and  for 
many  years  following,  the  genesis  of  rocks,  especially  of 
igneous  rocks,  was  a  subject  of  inquiry  and  of  prolonged 
discussion.  The  aid  of  the  rapidly  growing  science  of 
chemistry  was  invoked  by  the  geologists  and  analyses  of 
rocks  were  made  in  the  attempt  to  throw  light  on  impor- 


RISE  OF  PETROLOGY  AS  A  SCIENCE      249 

tant  questions.  It  is  remarkable,  also,  how  keen  were 
the  observations  that  the  geologists  of  those  days  made 
upon  the  rocks,  as  to  their  component  minerals  and 
structures,  aided  only  by  the  pocket  lens.  Many  ideas 
were  put  forward,  the  essentials  of  which  have  persisted 
to  the  present  day  and  have  become  interwoven  into  the 
science,  whereas  others  gave  rise  to  contentions  which 
have  not  yet  been  settled  to  the  satisfaction  of  all.  At 
times  in  these  earlier  days  the  microscope  was  called  into 
use  to  help  in  solving  questions  regarding  the  finer 
grained  rocks,  but  this  employment,  as  Zirkel  has  shown, 
was  merely  incidental,  and  no  definite  technique  or 
purpose  for  the  instrument  was  established. 

On  the  other  hand,  the  fact  that  up  to  the  middle  of  the 
last  century  a  large  store  of  information  relating  to  the 
occurrence  of  rocks,  and  to  the  mineral  composition  of 
those  of  coarser  grain,  and  somewhat  in  respect  to  their 
structure,  had  been  accumulated,  caused  attempts  in  one 
way  or  another  to  find  means  of  coordinating  these  data 
and  to  produce  classifications,  such  as  those  of  Von  Cotta 
and  Cordier.  The  history  of  these  attempts  at  classifi- 
cation, before  the  revelations  made  by  the  use  of  the 
microscope  had  become  general,  has  been  admirably 
reviewed  by  Whitman  Cross^  and  need  not  be  further 
enlarged  upon  here. 

That  a  considerable  amount  of  work  was  done  along 
chemical  lines  also  is  testified  to  by  the  publication  of 
Roth's  Tabellen  in  1861,  in  which  all  published  analyses  of 
rocks  up  to  that  date  were  collected.  What  was  accom- 
plished during  this  period  was  done  chiefly  on  the  con- 
tinent of  Europe,  and  little  attention  had  been  paid  to  the 
subject  of  rocks  either  in  America  or  in  Great  Britain — 
even  so  late  as  1870  Geikie  remarks,  as  referred  to  by 
Cross,^  that  there  was  no  good  English  treatise  on 
petrography,  or  the  classification  and  description  of 
rocks.  In  this  country  still  less  had  been  accomplished, 
interest  being  almost  wholly  confined  to  the  vigorous  and 
growing  sciences  of  geology  and  mineralogy.  This  was 
natural,  for  mineralogy  is  the  chief  buttress  on  which  the 
structure  of  petrology  rests  and  must  naturally  develop 
first,  especially  in  a  relatively  new  and  unexplored 
region,  whose  mineral  resources  first  attract  attention. 


250  A  CENTURY  OF  SCIENCE 

The  geologists  in  carrying  out  their  studies  also  observed 
the  rocks  as  they  saw  them  in  the  field  and  made  inci- 
dental reference  to  them,  but  investigations  of  the  rocks 
themselves  was  very  little  attempted.  An  inspection  of 
the  first  two  series  of  the  Journal  shows  relatively  little 
of  importance  in  petrology  published  in  this  country; 
a  few  analyses  of  rocks,  occasional  mention  of  mineral 
composition,  of  weathering  properties,  and  notices  of 
methods  of  classification  proposed  by  French  and  Ger- 
man geologists  nearly  exhaust  the  list. 

Introduction  of  the  Microscope, 

The  beginnings  of  a  particular  branch  of  science  are 
generally  obscure  and  rooted  so  imperceptibly  in  the 
foundations  on  which  it  rests  that  it  is  difficult  to  point 
to  any  particular  place  in  its  development  and  say  that 
this  is  the  start.  There  are  exceptions  of  course,  like  the 
remarkable  work  of  Willard  Gibbs  in  physical  chemistry, 
and  it  may  chance  that  the  happy  inspiration  of  a  single 
worker  may  give  such  direction  to  methods  of  investiga- 
tion as  to  open  the  gates  into  a  whole  new  realm  of 
research,  and  to  thus  create  a  separate  scientific  field,  as 
happened  in  Radiochemistry. 

This  is  what  occurred  in  petrology  when  Sorby  in 
England,  in  1858,^  pointed  out  the  value  of  the  micro- 
scope as  an  instrument  of  research  in  geologic  investiga- 
tions, and  demonstrated  that  its  employment  in  the  study 
of  thin  sections  of  rocks  would  yield  information  of  the 
highest  value.  Others  beside  Sorby  had  made  use  of  the 
microscope,  as  pointed  out  by  Zirkel,^  but,  as  he  indi- 
cates, no  one  before  him  had  recognized  its  value.  Dur- 
ing the  next  ten  years  or  so,  however,  its  recognition  was 
very  slow  and  the  papers  published  by  Sorby  himself 
were  mainly  concerned  in  settling  very  special  matters. 

As  Williams^  has  suggested,  the  greatest  service  of 
Sorby  was,  perhaps,  his  instructing  Zirkel  in  his  ideas 
and  methods,  for  the  latter  threw  himself  whole-heart- 
edly into  the  study  of  rocks  by  the  aid  of  the  microscope 
and  his  discoveries  stimulated  other  workers  in  this  field 
in  Germany,  his  native  country,  until  the  dawning  science 
of  petrology  began  to  assume  form.     A  further  step  for- 


RISE  OF  PETROLOGY  AS  A  SCIENCE      251 

ward  was  taken  in  1873  in  the  appearance  of  the  text- 
books of  ZirkeP  and  Rosenbusch^  which  collated  the 
knowledge  which  had  been  gained  and  furnished  the 
investigator  more  precise  methods  of  work.  It  is  diffi- 
cult for  the  student  of  to-day  to  realize  how  much  had 
been  learned  in  the  interval  and,  for  that  matter,  how 
much  has  been  gained  since  1873,  without  an  inspection 
of  these  now  obsolete  texts.  In  1863,  Zirkel,  who  was 
then  at  the  beginning  of  his  work,  said  in  his  first  paper 
presented  to  the  Vienna  Academy  of  Sciences^  that  if  he 
confined  himself  chiefly  to  the  structure  of  the  rocks 
investigated  and  of  their  component  minerals,  and  stated 
little  as  to  what  these  minerals  were,  the  reason  for  that 
was  because  ^^  although  the  microscope  serves  splendidly 
for  the  investigation  of  the  former  relations,  it  promises 
very  little  help  for  the  latter.  Labradorite,  oligoclase 
and  orthoclase,  augite  and  hornblende,  minerals  whose 
recognition  offers  the  most  important  problems  in 
petrography,  in  most  cases  cannot  be  distinguished  from 
one  another  under  the  microscope."  How  little  could 
Zirkel  have  foreseen,  at  this  time,  less  than  forty  years 
later,  that  not  only  could  labradorite  be  accurately 
determined  in  a  rock-section,  but  that  in  a  few  minutes  by 
the  making  of  two  or  three  measurements  on  a  properly 
selected  section,  its  chemical  composition  and  the  crys- 
tallographic  orientation  of  the  section  itself  could  be 
determined ! 

The  Thin  Section, 

Before  going  further  we  may  pause  here  a  moment  to 
consider  the  origin  and  development  of  the  thin  section, 
without  which  no  progress  could  have  been  made  in  this 
field  of  research.  When  we  reflect  upon  the  matter,  it 
seems  a  marvelous  thing  indeed  that  the  densest,  blackest 
rock  can  be  made  to  yield  a  section  of  the  1/1000  of  an 
inch  in  thickness,  so  thin  and  transparent  that  fine  print- 
ing can  be  easily  read  through  it,  and  transmitting  light 
so  clearly  that  the  most  high-powered  objectives  of  the 
microscope  can  be  used  to  discern  and  study  the  minutest 
structures  it  presents  with  the  same  capacity  that  they 
can  be  employed  upon  sections  of  organic  material  pre- 
pared by  the  microtome.     This  is  no  small  achievement. 


252  A  CENTURY  OF  SCIENCE 

The  first  thin  sections  appear  to  have  been  prepared  in 
1828  by  William  Nicol  of  Edinburgh,  to  whom  we  owe  the 
prism  which  carries  his  name.  He  undertook  the  making 
of  sections  from  fossil  wood  for  the  purpose  of  studying 
its  structure.  The  method  he  developed  was  in  principle 
the  same  as  that  employed  to-day,  where  machinery  is 
not  used;  that  is,  he  ground  a  flat  smooth  surface  upon 
one  side  of  a  chip  of  his  petrified  wood,  then  cemented 
this  to  a  bit  of  glass  plate  with  Canada  balsam,  and 
ground  down  the  other  side  until  the  section  was  suffi- 
ciently thin.  This  method  was  used  by  others  for  the 
study  of  fossil  woods,  coal,  etc.,  but  it  was  not  applied  to 
rocks  until  1850,  when  Sorby  used  it  for  investigating  a 
calcareous  grit.  Oschatz,  in  Germany,  also  about  this 
time  independently  discovered  the  same  method.  A  fur- 
ther advance  was  made  in  melting  the  cement,  floating  off 
the  slice,  and  transferring  it  to  a  suitable  object-glass 
with  cover,  a  process  still  employed  by  many;  though 
most  operators  now  cement  the  first  prepared  surface  of 
the  rock  chip  directly  to  the  object-glass,  and  mount  the 
section  without  transferring  it. 

Next  came  the  use  of  machinery  to  save  labor  in  grind- 
ing, and  another  step  was  made  in  the  introduction  of  the 
saw,  a  circular  disk  of  sheet  iron  whose  edge  was  fur- 
nished with  embedded  diamond  dust.  This  makes  it 
possible  to  cut  relatively  thin  slices  with  comparative 
rapidity,  but  the  final  grinding  which  requires  experience 
and  skill  must  still  be  done  by  hand.  Carborundum  has 
also  largely  replaced  emery.  The  skill  and  technique  of 
preparers  has  reached  a  point  where  sections  of  rocks  of 
the  desired  thinness  (0-001  inch),  and  four  or  five  inches 
square  have  been  exhibited. 

The  Era  of  Petrography, 

In  these  earlier  days  of  the  science,  as  noted  above, 
great  difficulty  was  at  first  experienced  in  the  recognition 
of  the  minerals  as  they  were  encountered  in  the  study  of 
rocks  under  the  microscope.  At  that  time  the  chemical 
composition  and  outward  crystal  form  of  minerals  were 
relatively  much  better  known  than  their  physical  and, 
especially,  their  optical  properties  and  constants.     Some 


EISE  OF  PETROLOGY  AS  A  SCIENCE      253 

beginnings  in  this  had  been  made  by  Brewster,  Nicol,  and 
other  physicists,  and  the  mineralogists  had  commenced 
to  study  minerals  from  this  viewpoint.  Especially 
Des  Cloiseaux  had  devoted  himself  to  determining  the 
optical  properties  of  many  minerals,  and  the  writer, 
when  a  student  in  the  laboratory  of  Rosenbusch  in  1890, 
well  recalls  the  tribute  that  he  paid  to  the  work  of 
Des  Cloiseaux  for  the  aid  which  it  had  afforded  him  in  his 
earlier  researches  in  petrography. 

The  twenty  years  following  the  publication  of  the 
texts  of  Rosenbusch  and  Zirkel  may  be  characterized  as 
the  era  of  microscopical  petrography.  A  distinction  is 
drawn  here  between  the  latter  word  and  petrology,  a 
distinction  often  overlooked,  for  petrography  means  lit- 
erally the  description  of  rocks,  whereas  petrology  denotes 
the  science  of  rocks.  As  time  passed  the  broader  and 
more  fundamental  features  of  rocks,  especially  of  igneous 
and  metamorphic  rocks,  in  addition  to  their  mineral 
constitution,  were  more  studied  and  gained  greater  recog- 
nition, petrography  gradually  became  a  department  of 
the  larger  field  of  petrology — the  science  of  to-day. 

The  use  of  the  microscope,  as  soon  as  the  method 
became  more  generally  understood,  opened  up  so  vast  a 
field  for  investigation  that  at  first  the  study  and  descrip- 
tion of  the  rocks  seemed  of  prime  importance.  This  was 
natural,  for  hitherto  the  finer  grained  rocks  had  for  the 
most  part  defied  any  adequate  elucidation  and  here  was  a 
key  which  enabled  one  to  read  the  cipher.  A  flood  of  lit- 
erature upon  the  composition,  structure,  and  other  char- 
acters of  rocks  from  all  parts  of  the  world  began  to 
appear  in  ever  increasing  volume.  The  demands  of  the 
petrographers  for  a  greater  and  more  accurate  knowledge 
of  the  physical  and  optical  constants  of  minerals  stimu- 
lated this  side  of  mineralogy,  and  increasing  attention 
was  given  to  investigations  in  this  direction.  No  definite 
line  between  the  two  closely  related  sciences  could  be 
drawn,  and  a  large  part  of  the  work  published  under  the 
heading  of  petrography  could  perhaps  be  as  well,  or 
better,  described  under  the  title  of  micro-mineralogy. 
To  some,  in  truth,  the  rocks  presented  themselves  simply 
as  aggregates  of  minerals,  occurring  in  fine  grains. 

The   work   of   the    German   petrographers    attracted 

16 


254  A  CENTURY  OF  SCIENCE 

attention  and  drew  students  from  all  parts  of  the  world 
to  their  laboratories,  especially  to  those  of  Zirkel  and 
Rosenbusch.  The  great  opportunities,  facilities,  and 
freedom  for  work  which  the  German  universities  had 
long  otfered  to  foreign  students  of  science  naturally- 
encouraged  this.  In  France  a  brilliant  school  of  petrolo- 
gists,  under  the  able  leadership  of  Michel-Levy  and 
Fouque,  had  arisen  whose  work  has  been  continued  by 
Barrois,  Lacroix  and  others,  but  the  rigid  structure  of 
the  French  universities  at  that  period  did  not  permit 
of  the  offering  of  great  inducements  for  the  attendance 
of  foreign  students.  The  work  of  the  French  petrog- 
raphers  will  be  noticed  in  another  connection. 

In  Great  Britain,  the  home  of  Sorby,  the  new  science 
progressed  at  first  slowly,  until  it  was  taken  up  by  All- 
port,  Bonney,  Judd,  Rutley,  and  others.  In  1885  the 
evidence  of  the  advance  that  had  been  made  and  of  the 
firm  basis  on  which  the  new  science  was  now  placed 
appeared  in  TealPs  great  work,  *^ British  Petrography,'' 
which  marked  an  epoch  in  that  country  in  petrographic 
publication.  This  work  was  of  importance  also  in 
another  direction  than  that  of  descriptive  petrography, 
in  that  it  contains  valuable  suggestions  for  the  applica- 
tion of  the  principles  of  modern  physical  chemistry  in 
solving  the  problems  of  the  origin  of  igneous  rocks.  In 
it,  as  in  the  publications  of  Lagorio,  we  see  the  passage  of 
the  petrographic  into  the  petrologic  phase  of  the  science. 

The  earliest  publication  in  America  of  the  results  of 
microscopic  investigation  of  rocks  that  the  writer  has 
been  able  to  find  is  by  A.  A.  Julien  and  C.  E.  Wright, 
chiefly  on  greenstones  and  chloritic  schists  from  the 
iron-bearing  regions  of  upper  Michigan.®  Naturally,  it 
was  of  a  brief  and  elementary  character.  In  1874  E.  S. 
Dana  read  a  paper  before  the  American  Association  for 
the  Advancement  of  Science  on  the  result  of  his  studies 
on  the  *^ Trap-rocks  of  the  Connecticut  valley,"  an 
abstract  of  which  was  published  in  this  Journal.^^ 
Meanwhile  Clarence  King,  in  charge  of  the  40th  Parallel 
survey,  feeling  the  need  of  a  systematic  study  of  the 
crystalline  rocks  which  had  been  encountered,  and  finding 
no  one  in  this  country  prepared  to  undertake  it,  had 
induced  Zirkel  to  give  his  attention  to  this  task.     The 


RISE  OF  PETROLOGY  AS  A  SCIENCE      255 

result  of  this  labor  appeared  in  1876  in  a  fine  volume^^ 
which  attracted  great  attention.  In  the  same  year 
appeared  also  petrographical  papers  by  J.  H.  Caswell,^ ^ 

E.  S.  Dana^^  and  G.  W.  Hawes.^^  The  latter  devoted 
himself  almost  entirely  to  this  field  of  research  and  may 
thus,  perhaps,  be  termed  the  earliest  of  the  petrog- 
raphers  in  this  country.  His  work,  ^*The  Mineralogy 
and  Lithology  of  New  Hampshire,'*  issued  in  1878  as  one 
of  the  reports  of  the  State  Survey  under  Prof.  C.  H. 
Hitchcock,  was  the  first  considerable  memoir  by  an 
American.  This  was  followed  by  various  papers,  one  on 
the  **  Albany  Granite  and  its  contact  phenomena, ''^^ 
being  of  especial  interest  as  one  of  the  earliest  studies  of 
a  contact  zone,  and  in  the  fullness  of  methods  employed 
in  attacking  the  problem  forecasting  the  change  to 
the  petrology  era. 

During  the  ten  years  following,  or  from  1880  to  1890, 
the  new  science  of  petrography  flourished  and  grew 
exceedingly.  Many  young  geologists  abroad  devoted 
themselves  to  this  field  of  research  and  the  store  of 
accumulated  knowledge  concerning  rocks  from  all  parts 
of  the  world,  and  their  relations  grew  apace.  The  work 
of  Teall  has  been  noticed  and  among  others  might  be 
mentioned  the  name  of  Brogger,  whose  first  contribu- 
tion^^ in  this  field  gave  evidence  that  his  publications 
would  become  classics  in  the  science. 

In  America  there  appeared  in  this  period  a  number  of 
eager  workers,  trained  in  part  in  the  laboratories  of 
Rosenbusch  and  Zirkel,  whose  researches  were  destined 
to  place  the  science  on  the  secure  footing  in  this  country 
which  it  occupies  to-day.  Among  the  earlier  of  these  may 
be  mentioned  Whitman  Cross,  R.  D.  Irving,  J.  P.  Iddings, 
G.  H.  Williams,  J.  F.  Kemp,  J.  S.  Diller,  B.  K.  Emerson, 
M.  E.  Wadsworth,  G.  P.  Merrill,  N.  H.  Winchell,  and 

F.  D.  Adams  in  Canada.  Others  were  added  yearly  to 
this  group.  As  a  result  of  their  work  a  constantly  grow- 
ing volume  of  information  about  the  rocks  of  America 
became  available,  and  one  has  only  to  examine  the  files 
of  the  Journal  and  other  periodicals  and  the  listed  pub- 
lications of  the  National  and  State  Surveys  to  appreciate 
this. 

In  the  Journal,  for  example,  we  may  refer  to  papers^^ 


256  A  CENTURY  OF  SCIENCE 

by  Emerson  on  the  Deerfield  dike  and  its  minerals,  and 
on  the  occurrence  of  nephelite  syenite  at  Beemersville, 
N.  J. ;  to  various  interesting  articles  by  Cross  on  lavas 
from  Colorado  and  the  pneumatolytic  and  other  min- 
erals associated  with  them;  to  important  papers  by 
Iddings  on  the  rocks  of  the  volcanoes  of  the  Northwest, 
and  those  of  the  Great  Basin,  to  primary  quartz  in 
basalt,  and  the  origin  of  lithophysae;  to  the  results  of 
researches  by  G.  H.  Williams  on  the  rocks  of  the  Cort- 
landt  series,  and  on  peridotite  near  Syracuse,  N.  Y. ;  to 
papers  by  Diller  on  the  peridotites  of  Kentucky,  and 
recent  volcanic  eruptions  in  California;  to  articles  by 
R.  D.  Irving  on  the  copper-bearing  and  other  rocks  of  the 
Lake  Superior  region,  and  to  Kemp  on  dikes  and  other 
eruptives  in  southern  New  York  and  northern  New 
Jersey.  Other  publications  would  greatly  extend  this 
list. 

The  Petrologic  Era, 

As  the  chief  facts  regarding  rocks,  especially  igneous 
rocks,  as  to  their  mineral  and  chemical  composition,  their 
structure  and  texture  and  the  limits  within  which  these 
are  enclosed,  became  better  known;  and  the  relations, 
which  these  bear  to  the  associations  of  rocks  and  their 
modes  of  occurrence,  began  to  be  perceived,  the  science 
assumed  a  broader  aspect.  The  perception  that  rocks 
were  no  longer  to  be  regarded  merely  as  interesting 
assemblages  of  minerals,  but  as  entities  whose  charac- 
ters and  associations  had  a  meaning,  increased.  More 
and  better  rock  analyses  stimulated  interest  on  the 
chemical  side  and  this  and  the  genesis  of  their  minerals 
led  to  a  consideration  of  the  magmas  and  their  func- 
tions in  rock-making.  The  fact  that  the  different  kinds 
of  rocks  were  not  scattered  indiscriminately,  but  that 
different  regions  exhibited  certain  groupings  with  com- 
mon characters,  was  noticed.  These  features  led  to 
attempts  to  classify  igneous  rocks  on  different  lines  from 
those  hitherto  employed,  and  to  account  for  their  origin 
on  broad  principles.  In  other  words,  the  descriptive 
science  of  petrography  merged  into  the  broader  one  of 
petrology.  No  exact  time  can  be  set  which  marks  this 
passage,  since  the  evolution  was  gradual.     Yet  for  this 


RISE  OF  PETROLOGY  AS  A  SCIENCE      257 

country,  in  reviewing  the  literature,  for  which  the  suc- 
cessive issues  of  the  ^*  Bibliography  of  North  American 
Geology '^  published  by  the  U.  S.  Geological  Survey  has 
been  of  the  greatest  value ;  the  writer  has  been  struck  by 
the  fact  that  in  the  first  volume  containing  the  index  of 
papers  down  to  and  including  1891,  the  articles  on  sub- 
jects of  this  nature  are  listed  under  the  heading  of 
petrography  J  whereas  in  the  second  volume  (1892-1900) 
they  are  grouped  under  petrology  and  the  former  head- 
ing is  omitted.  A  justification  for  this  is  found  in 
examining  the  list  of  publications  and  noting  their  char- 
acter. With  some  reason,  therefore,  the  beginning  of 
this  period  may  be  placed  as  in  the  early  years  of  this 
decade.  Furthermore,  it  was  at  this  time  that  the  great 
work  of  ZirkeP^  began  to  appear,  which  sums  up  so  com- 
pletely the  results  of  the  petrographic  era.  Rosenbusch^^ 
was  formulating  more  definitely  his  views  on  the  division 
of  rocks  into  magmatic  groups,  as  displayed  by  their 
associations  in  the  field,  and  using  this  in  classification; 
an  idea  which,  appearing  first  in  the  second  edition  of  his 
**  Physiographic  der  massigen  Gesteine,''  finds  fuller 
development  in  the  third  and  last  editions  of  this  work. 
In  this  country  Iddings^^  published  an  important  paper, 
in  which  the  family  relationships  of  igneous  rocks  and 
the  derivation  of  diverse  groups  from  a  common  magma 
by  differentiation  are  clearly  brought  out.  The  funda- 
mental problems  underlying  the  genesis  of  igneous  rocks 
had  now  been  clearly  recognized,  and  with  this  recogni- 
tion the  science  passed  into  the  petrologic  phase. 
Brogger^^  also  had  ascribed  to  the  alkalic  rocks  of  South 
Norway  a  common  parentage  and  had  pointed  out  their 
regional  peculiarities. 

From  this  time  forward  an  attempt  may  be  noted  to  find 
an  analogy  between  rocks  and  the  forms  of  organic  life 
and  to  apply  those  principles  of  evolution  and  descent, 
which  have  proved  so  fruitful  in  the  advancement  of  the 
biological  sciences,  to  the  genesis  and  classification  of 
igneous  rocks.  This,  perhaps,  has  on  the  whole  been 
more  apparent  than  real,  in  the  constant  borrowing  of 
terms  from  those  sciences  to  express  certain  features  and 
relationships  observed,  or  imagined,  to  obtain  among 
rocks.     Nevertheless,  the  perception  of  certain  relations 


258  A  CENTURY  OF  SCIENCE 

which  we  owe  so  largely  to  Rosenbusch  and  to  Brogger-^ 
has  proved  of  undoubted  value  in  furnishing  a  stimulus 
for  the  investigation  of  new  regions,  and  in  affording 
indications  of  what  the  petrologist  should  anticipate  in 
his  work. 

Thus,  the  labors  of  the  men  previously  mentioned,  with 
those  of  Bayley,  Bascom,  Cushing,  Daly,  Lane,  Lawson, 
Lindgren,  Pirsson,  J.  F.  Williams,  Washington,  and 
others,  have  thrown  a  flood  of  light  upon  the  igneous 
rocks  of  this  continent,  and  has  made  it  possible  to  draw 
many  broad  generalizations  concerning  their  origin  and 
distribution.  Thus,  the  differentiated  laccoliths  of  Mon- 
tana^^  have  been  of  service  in  affording  clear  examples  of 
the  process  of  local  diiferentiation.  Many  papers  pub- 
lished in  the  Journal  during  the  last  twenty  years  show 
this  evolution  and  growth  of  petrological  ideas.  The 
contributions  from  American  sources  during  this  later 
period,  and  of  which  those  in  the  Journal  form  a  consid- 
erable fraction,  have  indeed  been  of  great  weight  in 
shaping  the  development  and  future  of  the  science. 

By  referring  to  the  files  of  the  Journal,  it  will  be  seen 
that  they  cover  a  continually  widening  range  of  subjects 
concerning  rocks,  and  articles  of  theoretical  interest  are 
more  and  more  in  evidence,  along  with  those  of  a  purely 
descriptive  character.^^  Thus  we  find  discussions  by 
Becker  on  the  physical  constants  of  rocks,  on  fractional 
crystallization,  and  on  diiferentiation;  by  Cross  on 
classification;  by  Adams  on  the  physical  properties  of 
rocks ;  by  Daly  on  the  methods  of  igneous  intrusion ;  by 
•Wright  on  schistosity;  by  Fenner  on  the  crystallization 
of  basaltic  magma;  by  Bowen  on  differentiation  by 
crystallization;  by  the  writer  on  complementary  rocks 
and  on  the  origin  of  phenocrysts ;  by  Smyth  on  the  origin 
of  alkalic  rocks ;  by  Murgoci  on  the  genesis  of  riebeckite 
rocks ;  and  by  Barrell  on  contact-metamorphism.  These 
may  serve  as  examples,  selected  almost  at  random,  from 
the  files  of  the  Journal,  and  we  find  with  them  articles 
descriptive  of  the  petrology  of  many  particular  regions, 
which  often  contain  also  matter  of  general  interest  and 
importance,  such  as  papers  by  Lindgren  on  the  grano- 
diorite  and  related  rocks  of  the  Sierra  Nevada;  by 
Ransome  on  latite;   by  Cross  on  the  Leucite  Hills;   by 


EISE  OF  PETROLOGY  AS  A  SCIENCE      259 

Hague  on  the  lavas  of  the  Yellowstone  Park;  by  Pogne 
on  ancient  volcanic  rocks  from  North  Carolina ;  by  War- 
ren on  peridotites  from  Cumberland,  R.  I. ;  on  sandstone 
from  Texas  by  Goldman ;  and  on  the  petrology  of  vari- 
ous localities  in  central  New  Hampshire  by  Washington 
and  the  writer.  Such  a  list  could  of  course  be  much 
extended  and  other  papers  of  importance  be  cited,  but 
enough  has  been  said  to  indicate  how  important  a  reposi- 
tory of  the  results  of  petrologic  research  the  Journal  has 
been  and  continues  to  be. 

In  thus  looking  backward  over  the  list  of  active 
workers  we  are  involuntarily  led  to  pause  and  reflect 
how  great  a  loss  American  petrology  has  sustained  in 
the  premature  death  of  some  of  its  most  brilliant  and 
promising  exponents;  it  is  only  necessary  to  recall  the 
names  of  R.  D.  Irving,  G.  H.  Williams,  G.  W.  Hawes, 
J.  F.  Williams  and  Carville  Lewis,  to  appreciate  this. 

The  store  of  material  gathered  during  these  years  has 
led  to  the  publication  of  extensive  memoirs,  in  which  the 
science  is  treated  not  from  the  older  descriptive  side,  but 
from  the  theoretical  standpoint  and  of  classification.^^ 
In  these  works  strong  divergencies  of  views  and  opinions 
are  observed,  which  is  a  healthy  sign  in  a  developing 
science. 

It  should  be  also  noted  that  along  with  this  evolution 
on  the  theoretical  side  there  has  been  a  constant  improve- 
ment in  the  technique  of  investigating  rocks.  It  is  only 
necessary  to  compare  the  older  handbooks  of  Zirkel  and 
Rosenbusch  with  the  many  modern  treatises  on  petro- 
graphic  methods  to  be  assured  of  this.^^  It  is  due  on  the 
one  hand  to  the  vast  amount  of  careful  work  w^hich  has 
been  done  in  accurately  determining  the  physical  con- 
stants of  rock-minerals*  and  in  arranging  these  for  their 
determination  microscopically,  as  in  the  remarkable 
studies  on  the  feldspars  by  Michel-Levy,  and  on  the  other 
in  researches  on  the  apparatus  employed,  and  in  conse- 

*We  may  mention  here,  for  example,  the  work  in  mineralogy  of  Pen- 
field,  noticed  in  the  accompanying  chapter  on  mineralogy.  In  addition  to 
the  accurate  determination  of  the  composition  and  constants  of  many- 
minerals,  some  of  which  have  importance  from  the  petrographic  standpoint, 
we  owe  to  him  more  than  anyone  the  recognition  of  fluorine  and  hydroxy! 
in  a  variety  of  species,  and  thereby  the  perception  of  their  pneumatolytic 
origin.    His  papers  have  been  published  almost  entirely  in  the  Journal. 


260  A  CENTURY  OF  SCIENCE 

quent  improvements  in  them  and  in  ways  of  using  them, 
as  exemplified  in  the  delicately  accurate  methods  intro- 
duced by  Wright.^"^  The  development  of  the  microscope 
itself  as  an  instrument  of  research  in  this  field  and  in 
mineralogy  deserves  a  further  word  in  this  connection. 
The  first  step  toward  making  the  ordinary  microscope  of 
special  use  in  this  way  was  taken  by  Henry  Fox  Talbot 
of  England,  when  he  introduced  in  1834  the  employment 
of  the  recently  invented  nicol  prisms  for  testing  objects 
in  polarized  light.  The  modern  instrument  may  be  said 
to  date  from  the  design  offered  by  Rosenbusch  in  1876. 
Since  that  time  there  have  been  constant  improvements, 
almost  year  by  year,  until  the  instrument  has  become  one 
of  great  precision  and  convenience,  remarkably  well 
adapted  for  the  work  it  is  called  upon  to  perform,  with 
special  designs  for  various  kinds  of  use,  and  an  almost 
endless  number  of  accessory  appliances  for  research  in 
different  branches  of  mineralogy  and  crystallography,  as 
well  as  in  petrography  proper.^^  This  also  calls  to  mind 
the  fact  that  for  the  convenience  of  those  who  are  not  able 
to  use  the  microscope  special  manuals  of  petrology  have 
been  prepared  in  which  rocks  are  treated  from  the 
megascopic  standpoint.^^ 

Metamorphic  Rocks. 

In  this  connection  the  metamorphic  rocks  should  not 
be  forgotten.  They  afford  indeed  the  most  difficult 
problems  with  which  the  geologist  has  to  deal;  every 
branch  of  geological  science  may  in  turn  be  called  upon  to 
furnish  its  quota  for  help  in  solving  them.  Under  the 
attack  of  careful,  accurate  and  persistent  work  in  the 
field,  under  the  microscope  and  in  the  chemical  labora- 
tory, with  the  aid  of  the  garnered  knowledge  in  petrol- 
ogy, stratigraphy,  physiography,  and  other  fields  of 
geologic  science,  their  mystery  has  in  large  part  given 
way.  The  inaugural  work  of  Lehmann,  Lossen,  Barrois, 
Bonney,  Teall,  and  other  European  geologists,  was  par- 
alleled in  America  by  that  of  R.  D.  Irving,  owing  to  whose 
efforts  the  Lake  Superior  resrion  became  the  chief  place 
of  study  of  the  metamorphic  rocks  in  this  country. 
Irving  soon  obtained  the  assistance  of  G.  H.  Williams, 
who  had  been  engaged  in  the  study  of  such  rocks,  and  the 


RISE  OF  PETROLOGY  AS  A  SCIENCE      261 

latter  published  a  memoir  on  the  greenstone  schist  areas 
of  Menominee  and  Marquette  in  Michigan^^  which  will 
always  remain  one  of  the  classics  in  the  literature  of 
metamorphic  rocks.  Irving 's  own  contributions  to 
petrology,  though  valuable,  were  cut  short  by  his 
untimely  death,  but  the  study  of  this  region  under  the 
direction  of  his  associate  and  successor,  C.  R.  Van  Hise, 
with  his  co-laborers,  has  yielded  a  mass  of  information 
of  fundamental  importance  in  our  understanding  of  met- 
amorphism  and  the  crystalline  schists.  Its  fruitage 
appears  in  the  memoir  by  Van  Hise^^  which  is  the  author- 
itative work  of  reference  on  metamorphism,  and  in 
various  publications  by  him  and  his  assistants,  Bayley, 
Clements,  Leith,  and  others.  The  work  of  the  Canadian 
geologists,  and  of  Kemp,  Cushing,  Smyth  and  Miller  in 
the  Adirondack  region,  should  also  be  mentioned  in  con- 
nection with  this  field  of  petrology. 

Chemical  Analyses  of  Hocks, 

It  has  been  previously  pointed  out  that,  as  the  science 
of  petrology  grew,  chemical  investigations  of  rocks  in 
bulk  were  undertaken.  The  object  of  such  analyses  was 
to  obtain  on  the  one  hand  a  better  control  over  the 
mineral  composition  and  on  the  other  to  gain  an  idea  of 
the  nature  of  the  magmas  from  which  igneous  rocks  had 
formed.  The  earliest  analysis  of  an  American  rock  of 
which  I  can  find  record  is  of  a  *^wacke"  by  J.  W.  "Webster 
given  in  the  first  volume  of  the  Journal,  page  296,  1818. 

During  the  next  40  years  a  few  occasional  analyses 
were  undertaken  by  American  chemists,  by  C.  T.  Jackson, 
T.  Sterry  Hunt,  and  others.  In  1861,  Justus  Roth  pub- 
lished the  first  edition  of  his  Tabellen,  in  which  he 
included  all  analyses  which  had  been  made  to  that  date 
and  which  he  considered  were  worthy  of  preservation. 
Although,  naturally,  from  the  status  of  analytical  chem- 
istry up  to  that  time,  most  of  these  would  now  be  con- 
sidered rather  crude,  the  publication  of  the  work  was  of 
great  service  and  marked  an  epoch  in  geochemistry.  In 
these  tables  Roth  lists  four  analyses  of  American  igneous 
rocks,  two  from  the  Lake  Superior  region  by  Jackson 
and  J.  D.  Whitney  and  two  by  European  chemists,  one  of 
whom  was  Bunsen.     The  material  of  the  last  two  was  a 


262  A  CENTURY  OF  SCIENCE 

**dolerite''  and  the  same  locality  is  given  for  each — • 
*^  Sierra  Nevada  between  38°  and  41°'^  which  was  prob- 
ably considered  quite  precise  for  western  America  in 
those  days. 

From  these  feeble  beginnings  the  forward  progress  of 
petrology  on  the  chemical  side  in  this  country  has  been 
a  steady  one  until  its  development  has  reached  the  point 
which  will  be  indicated  in  what  follows. 

The  collection  of  material  by  the  various  State  surveys 
and  by  those  initiated  by  the  National  Government  led  to 
an  increasing  number  of  rocks  being  analyzed  during  the 
petrographio  period.  These  became  also  increasingly 
good  in  quality,  like  those  published  by  G.  W.  Hawes  in 
his  papers.  When,  however,  chemists  were  appointed  to 
definite  positions  on  the  staffs  of  the  Government  surveys 
and  especially  when,  after  the  organization  of  the  U.  S. 
Geological  Survey  in  1879,  a  general  central  laboratory 
was  founded  in  1883  with  F.  W.  Clarke  in  charge, 
then  a  new  era  in  the  chemical  investigation  of  rocks  may 
be  said  to  have  started.  In  this  connection  should  be 
mentioned  the  work  of  W.  F.  Hillebrand,  who  set  a  stand- 
ard of  accuracy  and  detail  in  rock  analysis  which  had  not 
hitherto  been  attempted.  As  a  consequence  of  his  accu- 
rate and  thorough  methods  and  results  the  mass  of 
analyses  performed  by  him  and  his  fellow  chemists  in 
this  laboratory  affords  us  the  greatest  single  contribu- 
tion to  chemical  petrology  which  has  been  made.  Up  to 
January,  1914,  the  report  of  Clarke^^  lists  some  8000 
analyses  of  various  kinds  made  in  this  laboratory  for 
geologic  purposes.  Nearly  everywhere  also  a  great 
improvement  in  the  quality  of  rock-analyses  is  to  be 
noted,  and  in  the  manuals  of  Hillebrand^^  and  Washing- 
ton^* the  rock  analyst  has  now  at  his  command  the 
methods  of  a  greatly  perfected  technique  which  should 
insure  him  the  best  results. 

Roth's  Tabellen  have  been  previously  mentioned;  sev- 
eral supplements  were  published,  but  after  his  death  a 
long  interval  elapsed  before  this  convenient  and  useful 
work  was  again  taken  up  by  Washington^^  and  Osann.^^ 
A  new  edition  of  Washington's  Tables  has  recently  been 
published,  listing  some  8600  analyses  of  igneous  rocks 
made  up  to  the  close  of  1913.^^ 


RISE  OF  PETROLOGY  AS  A  SCIENCE      263 

On  the  theoretical  side  also,  where  petrology  passes 
into  geology,  the  investigator  of  to-day  will  find  a  mass 
of  most  useful  and  accurate  data  well  discussed  in  the 
modern  representative  of  Bischof 's  Chemical  Geology — 
Clarke's  Data  of  Geochemistry.^^  The  advance  on  the 
chemical  side,  therefore,  has  been  quite  commensurate 
with  that  in  the  microscope  as  an  instrument,  and  in  the 
results  obtained  by  it. 

Physico-Chemical  Work, 

The  study  of  geological  results  by  experimental 
methods,  which  should  gain  information  concerning  the 
processes  by  which  those  results  are  caused,  and  the  con- 
ditions under  which  they  operate,  has  been  from  the 
earliest  days  of  the  developing  science  recognized  as 
most  important,  and  the  record  of  the  literature  shows 
considerable  was  done  in  this  direction.  Experimental 
work  in  modern  petrology  may,  however,  be  considered 
to  date  from  1882  when  Fouque  and  Michel-Levy^^  pub- 
lished the  results  of  their  extensive  researches  on  the 
synthesis  of  minerals  and  rocks  by  pyrogenous  methods. 
The  brilliant  experiments  of  the  French  petrologists  at 
once  attracted  attention,  and  since  that  time  a  consid- 
erable volume  of  valuable  work  has  been  done  in  this 
field  by  a  number  of  men,  among  whom  may  be  men- 
tioned Morozewicz,*^  Doelter,^^  Tamman,*^  ^nd  Meunier.^^ 
As  this  work  continued  the  results  of  the  rapid  advances 
made  in  physical  chemistry  began  to  be  applied  in  this 
field  with  increasing  value.  To  J.  H.  L.  Vogt  we  owe  a 
valuable  series  of  papers,^*  in  which  the  formation  of 
minerals  and  rocks  from  magmas  is  treated  from  this 
standpoint.  Most  important  of  all  for  the  future  of 
petrology  has  been  the  founding  in  Washington  of  the 
splendid  research  institution,  the  Carnegie  Geophysical 
Laboratory,  under  the  leadership  of  Dr.  A.  L.  Day  with 
its  corps  of  trained  physicists,  chemists  and  petrologists, 
devoted  to  the  solving  of  the  problems  which  the  progress 
of  geological  science  raises.  The  publications  of  this 
institution  (many  of  them  published  in  the  Journal)  are 
too  numerous  to  be  mentioned  here;  many  of  them 
treat  successfully  of  matters  of  the  greatest  importance 
in  petrology.     This  is  an  earnest  of  what  we  may  hope  in 


264  A  CENTURY  OF  SCIENCE 

the  future.  The  accumulation  of  the  exact  physical  and 
chemical  data,  which  is  its  aim,  will  serve  as  a  necessary 
check  to  hypothetical  speculation  and  bring  petrology, 
and  especially  petrogenesis,  in  line  with  the  other  more 
exact  sciences  by  furnishing  quantitative  foundations  for 
its  structure  of  theory  to  rest  upon. 

While  the  achievements  of  this  great  organization  seem 
to  minimize  the  work  of  the  individual  investigator  in 
this  field,  he  may  take  heart  by  observing  the  important 
results  on  the  strength  of  rocks  under  various  condi- 
tions which  have  been  obtained  by  Adams  in  recent  years, 
data  of  wide  application  in  theoretical  geology.  In  this 
field  also  a  special  text  has  appeared  in  which  the  prin- 
ciples and  acquired  data  are  given.^^ 

Summary, 

In  this  brief  retrospect,  giving  only  the  barest  outlines 
and  omitting  from  necessity  much  of  importance,  we  have 
seen  petrology  grow  from  occasional  crude  experiments 
into  a  fully  organized  science  in  the  last  half  century.  It 
has  to-day  a  well-perfected  technique,  a  large  volume 
of  literature,  texts  treating  of  general  principles,  of 
methods  of  work,  descriptive  handbooks  on  the  morph- 
ological side,  and  has  attained  general  recognition  as  a 
field,  which,  though  not  large,  is  worthy  of  the  concen- 
tration of  intellectual  endeavor.  Like  other  healthy 
growing  organisms  it  has  given  rise  to  offshoots,  and  the 
sciences  of  metallography  and  of  the  micro-study  of 
ore  deposits,  which  are  rapidly  assuming  form,  have 
branched  from  it. 

What  of  the  future  ?  The  old  days  of  mostly  descrip- 
tive work,  and  of  theorizing  purely  from  observed  results, 
have  passed.  The  science  has  entered  upon  the  stage 
where  work  and  theory  must  be  continually  brought  into 
agreement  with  chemical,  physical  and  mathematical 
laws  and  data,  and  in  the  application  of  these  new  prob- 
lems present  themselves.  As  we  climb,  in  fact,  new  hor- 
izons open  to  our  view  indicating  fresh  regions  for 
exploration,  for  acquiring  human  knowledge  and  for 
our  satisfaction. 


RISE  OF  PETROLOGY  AS  A  SCIENCE      265 

Bihliography, 

^W.  Cross,  Jour.  Geology,  10,  451,  1902. 

'  Ihid.,  p.  45. 

"  Sorby,  Quart.  Jour.  Geol.  Soc,  14,  453,  1858. 

*Zirkel,  Einfiihrung  des  Mikroskops  in  das  mineralogisch-geologische 
Studium,  1881. 

^  Williams,  G.  H.,  Modern  Petrography,  1886. 

'  Zirkel,  Mikroskopische  Beschaffenheit  der  Mineralien  und  Gesteine. 

'  Rosenbusch,  Mikroskopische  Physiographie  der  petrographisch  wichtigen 
Mineralien. 

*  Zirkel,  Mikroskopische  Gesteinstudien,  Sitzung  vom  12  Marz,  1863. 

'Julien  and  Wright,  Geol.  Surv.  of  Michigan,  2,  1873.  Appendices  A 
and  C. 

^•^  Dana,  E.  S.,  the  Journal,  8,  390-392,  1874. 

^^ Zirkel,  Geological  Exploration  of  the  40th  Parallel;  vol.  VI,  Micro- 
scopical Petrography. 

^'  Caswell,  Microscopical  Petrography  of  the  Black  Hills.  U.  S.  Geog. 
and  Geol.  Surv.  Rocky  Mts.  Rep.  on  Black  Hills  of  Dakota,  469-527.  The 
separate  copies  issued  bear  the  imprint  1876;    the  complete  report  1880. 

^*  Dana,  E.  S.,  Igneous  Rocks  in  the  Judith  Mts.  Rep,  of  Reconnaissance 
Carroll,  Mont.,  to  Yellowstone  Park  in  1875.  Col.  Wm.  Ludlow,  War 
Dept.,  Washington,  105-106. 

"  Hawes,  G.  W.,  Rocks  of  the  Chlorite  Formation,  etc.,  the  Journal,  11, 
122-126,  1876.  Greenstones  of  New  Hampshire,  etc.,  ibid.,  12,  129-137, 
1876. 

^' Hawes,  G.  W.,  the  Journal,  21,  21-32,  1881. 

"Brogger,  Die  silurischen  Etagen  2  und  3,  Kristiania,  1882. 

"  The  references  for  the  papers  alluded  to,  all  of  them  in  the  Journal, 
are  as  follows: 

Emerson,  24,  195-202,  270-278,  349-359,  1882; 

,  23,  302-308,  1882. 

Cross,  27,  94-96,  1884;  31,  432-438,  1886;  39,  359-370,  1890;  41,  466- 
475,1891;  23,452-458,1882. 

Iddings,  26,  222-235,  1883; 

,  27,  453-463,  1884; 

,  36,  208-221,  1888; 

,  33,  36-45,  1887. 

Williams,  31,  26-41,  1886;  33,  135-144,  191-199,  1887;  35,  433-448, 
1888;  36,  254-259,  1888. 

,  34,  137-145,  1887. 

DUler,  32,  121-125,  1886;    37,  219-220,  1889; 

,  33,  45-50,  1887. 

Irving  (26,  27-32,  321-322,  27,  130-134,  1883;    29,  358-359,  1885). 

Kemp  (35,  331-332,  1888;    36,  247-253,  1888;    38,  130-134,  1889). 

'*  Zirkel,  Lehrbuch  der  Petrographie,  2d  ed.,  1893. 

"Hunter  and  Rosenbusch,  Ueber  Monchiquit,  etc.,  Min.  petr.  Mitth.,  11, 
445,  1890.  Rosenbusch,  Ueber  Structur  und  Class,  der  Eruptivgesteine, 
ibid.,  12,  351,  1891. 

^Iddings,  Origin  of  Igneous  Rocks,  Bull.  Phil,  Soc  Washington,  12, 
89-213,  1892.    ,  ,  s       »     -» 

J^Brogger,   Mineralien    der   Syenit-pegmatit-gange,    etc.,   Zs.    Kryst.,    16, 
1890. 


" >  Basic  Eruptive  Rocks  of  Gran,  Quart.  Jour.  Geol.  Soc,  50, 

15,  1894;    Grorudit-Tinguait-Serie,  Vidensk.  Skrift.  1  Math.  nat.  Kl.,  No. 
4,  1894. 


266  A  CENTURY  OF  SCIENCE 

^  Weed  and  Pirsson,  e.  g.  Shonkin  Sag,  the  Journal,  12,  1-17,  1901. 

-*  The  references  for  the  articles  mentioned  (all  in  the  Journal)  are  as 
follows : 

Becker,  46,  1893;    4,  257,  1897;    3,  21-40,  1897. 

Cross,  39,  657-661,  1915. 

Adams,  22,  95-123,  1906;    29,  465-487,  1910. 

Daly,  22,  195-216,  1906;    26,  17-50,  1908. 

Wright,  22,  224-230,  1906. 

Fenner,  29,  217-234,  1910. 

Bowen,  39,  175-191 ;    40,  161-185,  1915. 

Pirsson,  50,  116-121,  1895;    7,  271-280,  1899. 

Smyth,  36,  33-46,  1913. 

Murgoci,  20,  133-145,  1905. 

Barren,  13,  279-296,  1902. 

Lindgren,  3,  301-314,  1897;    9,  269-282,  1900. 

Ransome,  5,  355-375,  1898. 

Cross,  4,  115-141,  1897. 

Hague,  1,  445-457,  1896. 

Pogue,  28,  218-238,  1909. 

Warren,  25,  12-36,  1908. 

Goldman,  39,  261-288,  1915. 

Washington  and  Pirsson,  Belknap  Mts.,  20,  344-353,  1905;  22,  439-457, 
493-515,  1906. 

,  Red  HHl,  23,  257-276,  433-447,  1907. 

,  Tripyramid  Mt.,  31,  405-431,  1911. 

-^  Quantitative  Classification  of  Igneous  Rocks,  Cross,  Iddings,  Pirsson 
and  Washington,  Chicago,  1903. 

Petrogenesis,  C.  Doelter,  Braunschweig,  1906. 

Igneous  Rocks,  vols.  1  and  2,  J.  P.  Iddings,  New  York,  1909  and  1913. 

Problem  of  Volcanism,  Iddings,  New  Haven,  1914. 

Natural  History  of  Igneous  Rocks,  Alfred  Harker,  London,  1909. 

Igneous  Rocks  and  their  Origin,  R.  A.  Daly,  New  York,  1914. 

^  Among  these  may  be  mentioned: 

Rosenbusch  u.  Wiilfing,  Physiog.  der  petrog.  wicht.  Min.,  Stuttgart,  1905. 

Iddings,  J.  P.,  Rock-Minerals,  1st  ed..  New  York,  1906. 

Johannsen,  A.,  Manual  of  Petrographic  Methods,  New  York,  1914. 

Winchell,  N.  H.  and  A.  N.,  Elements  of  Optical  Mineralogy,  New  York, 
1909. 

"  Wright,  Methods  of  Petrographic-Microscopic  Research,  Carnegie  Inst., 
Washington,  1911,  and  various  papers;    many  in  the  Journal. 

^Conf.  Wright's  work  quoted  above  and  the  various  manuals  previously 
mentioned. 

^Kemp,  Hand-book  of  Rocks,  3d  ed.,  New  York,  1904.  Pirsson,  Rocks 
and  Rock-Minerals,  New  York,  1910. 

""Williams,  G.  H.,  U.  S.  Geol.  Surv.,  Bull.  62,  Washington,  1890. 

^  Van  Hise,  Treatise  on  Metamorphism,  U.  S.  Geol.  Surv.,  Monograph  17. 

"^  F.  W.  Clarke,  U.  S.  Geol.  Surv.,  Bull.  591,  1915. 

^  Hillebrand,  Analysis  of  Silicate  and  Carbonate  Rocks,  U.  S.  Geol.  Surv., 
Bull.  422,  1910. 

"Washington,  Chemical  Analysis  of  Rocks,  pp.  200,  New  York,  1910. 

^Id.,  Chemical  Analyses  of  Igneous  Rocks  (1884-1900),  U.  S.  Geol.  Surv., 
Prof.  Paper,  No.  14,  1903. 

"^Osann,  Beitr.  zu  chem.  Petrogr.,  II  Teil.  Anal.  d.  Eruptivgest.,  1884- 
1900,  Stuttgart,  1905. 

^^  Washington,  ibid.,  2d  ed.,  U.  S.  Geol.  Surv.,  Prof.  Paper  99,  pp.  1216, 
1917. 


EISE  OF  PETROLOGY  AS  A  SCIENCE      267 

«« Clarke,  V.  S.  Geol.  Surv.,  Bull.  616,  1916. 

"'Fouque  and  Michel-Levy,  Synthese  des  Mineraux  et  des  Eoches,  Paris, 
1882. 

*"  Morozewicz,  Exper.  Untersuch.  u.  Bildung  der  Min.  im  Magma,  Min. 
petr.  Mitt.,  18,  1898. 

*»Doelter,  Synthetische  Studien,  N.  Jahrb.  Min.  1897,  1,  1-26.  AUg. 
chem.  Mineralogie,  etc. 

*^  Tamman,  Krystallisieren  und  Schmelzen,  1903. 

*^St.  Meunier,  Les  Methodes  de  Synthase  en  Mineralogie,  Paris,  1891. 

^'Vogt,  Mineralbildung  in  Smelzmassen,  Christiania,  1892;  Silikatschmelz- 
losungen,  1  and  2,  1903,  1904,  and  various  other  papers,  esp.  in  Min.  petr. 
Mitt.,  vols.  24  and  25,  1906. 

*H.  E.  Boeke,  Grundlagen  der  physikaliseh-chemischen  Petrographie, 
Berlin,  1915. 


VIII 

THE  GROWTH  OF  MINERALOGY  FROM 
1818  TO  1918 

By  WILLIAM  E.  FORD 

MINERALOGY  to-day  would  certainly  be  generally 
considered  one  of  the  minor  members  of  the 
group  of  the  Geological  Sciences.  We  commonly 
look  upon  it  in  the  light  of  an  useful  handmaiden,  whose 
chief  function  is  to  serve  the  other  branches,  and  we  are 
inclined  to  forget  that,  in  reality,  mineralogy  was  the  first 
to  be  recognized  and,  with  considerable  truth,  might  be 
claimed  as  the  mother  of  all  the  others.  Minerals, 
because  of  their  frequent  beauty  of  color  and  form,  and 
their  uses  as  gems  and  as  ornamental  stones,  were  the 
first  inorganic  objects  to  excite  wonder  and  comment  and 
we  find  many  of  them  named  and  described  in  very  early 
writings.  Theophrastus  (368-284  B.  C),  a  famous  pupil 
of  Aristotle,  wrote  a  treatise  ^  ^  On  Stones ' '  in  which  he 
collected  a  large  amount  of  information  about  minerals 
and  fossils.  The  elder  Pliny  (23-79  A.  D.),  more  than 
three  centuries  later,  in  his  Natural  History,  described 
and  named  many  of  the  commoner  minerals.  At  this  time 
it  was  natural  that  no  clear  distinction  should  be  drawn 
between  minerals  and  rocks,  or  even  between  minerals 
and  fossils.  As  long  as  all  study  of  the  materials  of  the 
earth's  crust  was  concerned  with  their  superficial  char- 
acters, it  was  logical  to  include  everything  under  the 
single  head.  There  were  some  writers  in  the  early  cen- 
turies of  the  Christian  era,  however,  who  believed  that 
fossils  had  been  derived  from  living  animals  but  the 
majority  considered  them  to  be  only  strange  and  unusual 
forms  of  minerals.  During  many  succeeding  centuries 
little  was  added  to  the  general  store  of  geological  knowl- 
edge and  it  was  not  until  the  beginning  of  the  sixteenth 


GROWTH  OF  MINERALOGY  269 

century,  that  any  further  notable  progress  was  made. 
Agricola  (1494-1555)  was  a  physician,  who,  for  a  time, 
lived  in  the  mining  district  of  Joachimstal.  He  studied 
and  described  the  minerals  that  he  collected  there.  He 
was  the  first  to  give  careful  and  critical  descriptions  of 
minerals,  of  their  crystals  and  general  physical  proper- 
ties. Unfortunately,  he  also  did  not  realize  the  funda- 
mental distinction  between  fossils  and  minerals,  and 
probably  because  of  his  influence  this  error  persisted, 
even  until  the  middle  of  the  eighteenth  century.  But, 
naturally,  as  the  number  of  scientific  students  increased, 
the  number  of  those  who  rejected  this  conclusion  grew, 
until  at  last,  the  true  character  of  fossils  was  established. 
The  keen  interest  in  minerals  and  fossils  which  was 
aroused  by  this  controversy,  together  with  the  rapid 
extension  of  mining  operations,  drew  the  attention  of 
scientific  men  to  other  features  of  the  earth  ^s  surface 
and  led  to  a  more  extended  investigation  of  its  characters 
and  thus  to  the  development  of  geology  proper.  It  is 
interesting  to  note  also  that  mineralogy  was  the  first  of 
the  Geological  Sciences  to  be  officially  recognized  and 
taught  by  the  universities. 

Although,  as  has  been  shown,  the  beginnings  of  min- 
eralogy lie  in  the  remote  past,  the  science,  as  we  know  it 
to-day,  can  be  said  to  have  had  practically  its  whole 
growth  during  the  last  one  hundred  years.  Of  the  more 
than  one  thousand  mineral  species  that  may  now  be  con- 
sidered as  definitely  established  hardly  more  than  two 
hundred  were  known  in  the  year  1800  and  these  were  only 
partially  described  or  understood.  It  is  true  that  Haiiy, 
the  *  ^father  of  crystallography,"  had  before  this  date  dis- 
covered and  formulated  the  laws  of  crystal  symmetry, 
and  had  shown  that  rational  relations  existed  between 
the  intercepts  upon  the  axes  of  the  different  faces  of  a 
crystal.  It  was  not  until  1809,  however,  that  Wollaston 
described  the  first  form  of  a  reflecting  goniometer,  and 
thus  made  possible  the  beginning  of  exact  investigation 
of  crystals.  The  distinctions  between  the  different  crys- 
tal groups  were  developed  by  Bernhardi,  Weiss  and  Mohs 
between  the  years  1807  and  1820,  while  the  Naumann 
system  of  crystal  symbols  was  not  proposed  until  1826. 
The  fact  that  doubly  refracting  minerals  also  polarize 

17 


270  A  CENTURY  OF  SCIENCE 

light  was  discovered  by  Mains  in  1808,  and  in  1813 
Brewster  first  recognized  the  optical  differences  between 
uniaxial  and  biaxial  minerals.  The  modern  science  of 
chemistry  was  also  just  beginning  to  develop  at  this 
period,  enabling  mineralogists  to  make  analyses  more 
and  more  accurately  and  thus  by  chemical  means  to 
establish  the  true  character  of  minerals,  and  to  properly 
classify  them. 

Franz  von  Kobell,  on  page  372  of  his  *  *  Geschichte  der 
Mineralogie, ' '  somewhat  poetically  describes  the  condi- 
dition  of  the  science  at  this  period  as  follows :  *  ^  With  the 
end  of  the  eighteenth  and  the  commencement  of  the  nine- 
teenth centuries  exact  investigations  in  mineralogy  first 
began.  The  mineralogist  was  no  longer  content  with 
approximate  descriptions  of  minerals,  but  strove  rather 
to  separate  the  essential  facts  from  those  that  were  acci- 
dental, to  discover  definite  laws,  and  to  learn  the  rela- 
tions between  the  physical  and  chemical  characters  of  a 
mineral.  The  use  of  mathematics  gave  a  new  aspect  to 
crystallography,  and  the  development  of  the  optical 
relationships  opened  a  magnificent  field  of  wonderful 
phenomena  which  can  be  described  as  a  garden  gay  with 
flowers  of  light,  charming  in  themselves  and  interesting 
in  their  relations  to  the  forces  which  guide  and  govern  the 
regular  structure  of  matter. ' ' 

In  the  Medical  Repository  (vol.  2,  p.  114,  New  York, 
1799),  there  occurs  the  following  notice :  **  Since  the  pub- 
lication of  the  last  number  of  the  Repository  an  Associa- 
tion has  been  formed  in  the  city  of  New  York  *for  the 
investigation  of  the  Mineral  and  Fossil  bodies  which  com- 
pose the  fabric  of  the  Globe;  and,  more  especially,  for 
the  Natural  and  Chemical  History  of  the  Minerals  and 
Fossils  of  the  United  States,'  by  the  name  and  style 
of  The  American  Mineralogical  Society."  "With  this 
announcement  is  given  an  advertisement  in  which  the 
society  **  earnestly  solicits  the  citizens  of  the  United 
States  to  communicate  to  them,  on  all  mineralogical  sub- 
jects, but  especially  on  the  following:  1,  concerning 
stones  suitable  for  gun  flints ;  2,  concerning  native  brim- 
stone or  sulphur ;  3,  concerning  salt-petre ;  4,  concerning 
mines  and  ores  of  lead. ' '    Further  the  society  asks  *  *  that 


GROWTH  OF  MINERALOGY  271 

specimens  of  all  kinds  be  sent  to  it  for  examination  and 
determination. ' ' 

This  marks  apparently  the  beginning  of  the  serious 
study  of  the  science  of  mineralogy  in  the  United  States. 
From  this  time  on,  articles  on  mineralogical  topics 
appeared  with  increasing  frequency  in  the  Medical 
Repository.  Most  of  these  were  brief  and  were  largely 
concerned  with  the  description  of  the  general  characters 
and  modes  of  occurrence  of  various  minerals.  Nothing 
of  much  moment  from  the  scientific  point  of  view 
appeared  until  many  years  later,  but  the  growing  inter- 
est in  things  mineralogical  was  clearly  manifest.  An 
important  stimulus  to  this  increasing  knowledge  and  dis- 
cussion was  furnished  by  Col.  George  Gibbs  who,  about 
the  year  1808,  brought  to  this  country  a  large  and  notable 
mineral  collection.  In  the  Medical  Repository  (vol.  11, 
p.  213, 1808),  is  found  a  notice  of  this  collection,  a  portion 
of  which  is  reproduced  below: 

*' Gibbs'  grand  Collection  of  Minerals.     ^ 

One  of  the  most  zealous  cultivators  of  mineralogy  in  the 
United  States  is  Col.  G.  Gibbs  of  Rhode  Island  and  his  taste  and 
his  fortune  have  concurred  in  making  him  the  proprietor  of  the 
most  extensive  and  valuable  assortment  of  minerals  that  prob- 
ably exists  in  America. 

This  rich  collection  consists  of  the  cabinets  possessed  by  the 
late  Mons.  Gigot  D'Orcy  of  Paris  and  the  Count  Gregoire  de 
Rozamonsky,  a  Russian  nobleman,  long  resident  in  Switzerland. 
To  which  the  present  proprietor  has  added  a  number,  either 
gathered  by  himself  on  the  spot,  or  purchased  in  different  parts 
of  Europe  .  .  .  The  whole  consists  of  about  twenty  thousand 
specimens.  A  small  part  of  this  collection  was  opened  to 
amateurs  at  Rhode  Island,  the  last  summer,  and  the  next,  if 
circumstances  permit,  the  remainder  will  be  exposed." 

In  1802  Benjamin  Silliman  was  appointed  professor  of 
chemistry  and  mineralogy  in  Yale  College.  After  the 
Gibbs  Collection  was  brought  to  America  he  spent  much 
time  with  the  owner  in  studying  it  and,  as  a  result,  Col. 
Gibbs  offered  to  place  the  collection  on  exhibition  in  New 
Haven  if  suitable  quarters  would  be  furnished  by  the  col- 
lege. This  was  quickly  accomplished  and  in  1810,  1811 
and  1812  the  collection  was  transferred  to  New  Haven 


272  A  CENTURY  OF  SCIENCE 

and  arranged  for  exhibition  by  Col.  Gibbs.  Later,  in 
1825,  it  was  purchased  by  Yale  and  served  as  the  nucleus 
about  which  the  present  Museum  collection  of  the  Univer- 
sity has  been  formed.  There  is  no  doubt  but  that  the 
presence  at  this  early  date  of  this  large  and  unusual  min- 
eral collection  had  a  great  influence  upon  the  develop- 
ment of  mineralogical  science  at  Yale,  and  in  the  country 
at  large. 

In  the  year  1810  Dr.  Archibald  Bruce  started  the 
*^ American  Mineralogical  Journal,''  the  title  page  of 
which  reads  in  part  as  follows :  ^  *  The  American  Mineral- 
ogical Journal,  being  a  Collection  of  Facts  and  Observa- 
tions tending  to  elucidate  the  Mineralogy  and  Geology  of 
the  United  States  of  America,  together  with  other  Infor- 
mation relating  to  Mineralogy,  Geology  and  Chemistry, 
derived  from  Scientific  Sources.''  Unfortunately  the 
health  of  Dr.  Bruce  failed,  and  the  journal  lasted  only 
through  its  first  volume.  It  had,  however,  *^been  most 
favorably  received,"  as  Silliman  remarks,  and  it  was  felt 
that  another  journal  of  a  similar  type  should  be  insti- 
tuted. Such  a  suggestion  was  made  by  Col.  Gibbs  to 
Professor  Silliman  in  1817  and  this  led  directly  to  the 
founding  of  the  American  Journal  of  Science  in  1818 
under  the  latter 's  editorship.  Although  the  field  of  the 
Journal  at  the  very  beginning  was  made  broad  and  inclu- 
sive it  has  always  published  many  articles  on  mineralog- 
ical subjects.  Three  of  its  editors-in-chief  have  been 
eminent  mineralogists,  and  without  question  it  has  been 
the  most  important  single  force  in  the  development  of 
this  science  in  the  country.  More  than  800  well-estab- 
lished mineral  species  have  been  described  since  the  year 
1800,  of  which  approximately  150  have  been  from  Amer- 
ican sources.  More  than  two-thirds  of  the  articles 
describing  these  new  American  minerals  have  first 
appeared  in  the  pages  of  the  Journal.  While  the 
description  of  new  species  is  not  always  the  most  import- 
ant part  of  mineralogical  investigation,  still  these  fig- 
ures serve  to  show  the  large  part  that  the  Journal  has 
played  in  the  growth  of  American  mineralogy. 

It  is  convenient  to  review  the  progress  in  Mineralogy 
according  to  the  divisions  formed  by  the  different  series, 
consisting  of  fifty  volumes  each,  in  which  the  Journal  has 


GROWTH  OF  MINERALOGY  273 

been  published.  These  divisions  curiously  enough  will 
be  found  to  correspond  closely  to  four  quite  definite 
phases  through  which  mineralogical  investigation  in 
America  has  passed.  The  first  series  covered  the  years 
from  1817  to  1845.  In  looking  through  these  volumes 
one  finds  a  large  number  of  mineralogical  articles,  the 
work  of  many  contributors.  The  great  majority  of  these 
papers  are  purely  descriptive  in  character,  frequently 
giving  only  general  accounts  of  the  mineral  occurrences 
of  particular  regions.  However,  a  number  of  articles 
dealing  with  more  detailed  physical  and  chemical  descrip- 
tions of  rare  or  new  species  also  belong  in  this  period. 
Among  the  mineralogists  engaged  at  this  time  in  the 
description  of  individual  species,  none  was  more  inde- 
fatigable than  Charles  U.  Bhepard.  He  was  graduated 
from  Amherst  College  in  1824,  at  the  age  of  twenty.  In 
1827  he  became  assistant  to  Professor  Silliman  in  New 
Haven,  continuing  in  this  position  for  four  years.  Later 
he  was  a  lecturer  in  natural  history  at  Yale,  and  was  at 
various  times  connected  with  Amherst  College  and  the 
South  Carolina  Medical  College  at  Charleston.  His 
articles  on  mineralogy  were  very  numerous.  He  assigned 
a  large  number  of  new  names  to  minerals,  although  with 
the  exception  of  some  half  dozen  cases,  these  have  later 
been  shown  to  be  varieties  of  minerals  already  known  and 
described,  rather  than  new  species.  In  spite,  however,  of 
his  frequent  hasty  and  inaccurate  decision  as  to  the  char- 
acter of  a  mineral,  his  influence  on  the  progress  of 
mineralogy  was  marked.  His  great  enthusiasm  and 
ceaseless  industry  throughout  a  long  life  could  not  help 
but  make  a  definite  contribution  to  the  science.  His 
*' Treatise  on  Mineralogy"  will  be  spoken  of  in  a  later 
paragraph.  He  died  in  May,  1886,  having  published  his 
last  paper  in  the  Journal  in  the  previous  September. 

The  first  book  on  mineralogy  published  in  America  was 
that  by  Parker  Cleaveland,  professor  of  mathematics,  nat- 
ural philosophy,  chemistry  and  mineralogy  in  Bowdoin 
College.  The  first  edition  was  printed  in  1816  and  an 
exhaustive  notice  is  given  in  the  first  volume  of  the  Jour- 
nal (1,  35,  308,  1818) ;  a  second  edition  followed  in  1822. 
In  his  preface  Cleaveland  gives  an  interesting  discussion 
concerning  the  two  opposing  European  methods  of  classi- 


274  A  CENTURY  OF  SCIENCE 

fying  minerals.  The  German  school,  led  by  Werner, 
classified  minerals  according  to  their  external  characters 
while  the  French  school,  following  Haiiy,  put  the  empha- 
sis on  the  ^^true  composition.'*  Cleaveland  remarks  that 
*^the  German  school  seems  to  be  most  distinguished  by  a 
technical  and  minutely  descriptive  language;  and  the 
French,  by  the  use  of  accurate  and  scientific  principles  in 
the  classification  or  arrangement  of  minerals/'  He, 
himself,  tried  to  combine  in  a  measure  the  two  methods, 
basing  the  fundamental  divisions  upon  the  chemical  com- 
position and  using  the  accurate  description  of  the  physi- 
cal properties  to  distinguish  similar  species  and  varieties 
from  each  other. 

Cleaveland 's  mineralogy  was  followed  nearly  twenty 
years  later  by  the  Treatise  on  Mineralogy  by  Charles 
U.  Shepard  already  mentioned.  The  first  part  of  this 
book  was  published  in  1832.  This  contained  chiefly  an 
account  of  the  natural  history  classification  of  minerals 
according  to  the  general  plan  adopted  by  Mohs,  the 
Austrian  mineralogist.  The  second  part  of  the  book, 
which  appeared  in  1835,  gave  the  description  of  indi- 
vidual species,  the  arrangement  here  being  an  alpha- 
betical one  throughout.  Subsequent  editions  appeared 
in  1844,  1852  and  1857. 

James  Dwight  Dana  was  graduated  from  Yale  College 
in  1833  at  the  age  of  twenty.  Four  years  later  (1837)  he 
published  ^'The  System  of  Mineralogy/'  a  volume  of  580 
pages.  The  appearance  of  this  book  was  an  event  of 
surpassing  importance  in  the  development  of  the  science. 
The  book,  of  course,  depended  largely  upon  the  previous 
works  of  Haiiy,  Mohs,  Naumann  and  other  European 
mineralogists,  but  was  in  no  sense  merely  a  compilation 
from  them.  Dana,  particularly  in  his  discussion  of 
mathematical  crystallography,  showed  much  original 
thought.  He  also  proved  his  originality  by  proposing 
and  using  an  elaborate  system  of  classification  patterned 
after  those  already  in  use  in  the  sciences  of  botany  and 
zoology.-  He  later  became  convinced  of  the  undesira- 
bility  of  this  method  of  classification  and  abandoned  it 
entirely  in  the  fourth  edition  of  the  System,  published  in 
1854,  substituting  for  it  the  chemical  classification  which, 
in  its  essential  features,  is  in  general  use  to-day.     The 


GROWTH  OF  MINERALOGY  275 

System  of  Mineralogy  started  in  this  way  in  1837,  has 
continued  by  means  of  successive  editions  to  be  the  stand- 
ard reference  book  in  the  subject.  The  various  editions 
appeared  as  follows:  I,  1837;  II,  1844;  III,  1850; 
IV,  1854;  V,  1868;  VI,  1892  (by  Edward  S.  Dana). 

J.  D.  Dana  also  contributed  numerous  mineralogical 
articles  to  the  first  series  of  volumes  of  the  Journal. 
It  is  interesting  to  note  that  they  are  chiefly  concerned 
with  the  more  theoretical  aspects  of  the  subject,  in  fact 
they  constitute  practically  the  only  articles  of  such  a 
character  that  appeared  during  this  period.  Among  the 
subjects  treated  were  crystallographic  symbols,  forma- 
tion of  twin  crystals,  pseudomorphism,  origin  of  minerals 
in  metamorphosed  limestones,  origin  of  serpentine, 
classification  of  minerals,  etc. 

The  volumes  of  the  Second  Series  of  the  Journal  cov- 
ered the  years  from  1846  through  1870.  This  period  was 
characterized  by  great  activity  in  the  study  of  the  chem- 
ical composition  of  minerals.  A  number  of  skilled 
chemists,  notably  J.  Lawrence  Smith,  George  J.  Brush 
and  Frederick  A.  Genth,  began  about  1850  a  long  series 
of  chemical  investigations  of  American  minerals.  Very 
few  articles  during  this  time  paid  much  attention  to  the 
physical  properties  of  the  minerals  under  discussion, 
practically  no  description  of  optical  characters  was 
attempted,  and  only  occasionally  were  the  crystals  of  a 
mineral  mentioned.  J.  D.  Dana  was  almost  the  only 
writer  who  constantly  endeavored  to  discover  the  funda- 
mental characters  and  relationships  in  minerals.  He 
published  many  articles  in  these  years  which  were  con- 
cerned chiefly  with  the  classification  and  grouping  of 
minerals,  with  similarities  in  the  crystal  forms  of  dif- 
ferent species,  with  relations  between  chemical  compo- 
sition and  crystal  form,  chemical  formulas,  mineral 
nomenclature,  etc.  The  following  titles  give  an  idea  of 
the  character  of  the  more  important  series  of  articles  by 
him  which  belong  to  this  category:  On  the  isomorphism 
and  atomic  volume  of  some  minerals  (9,  220, 1850) ;  vari- 
ous notes  and  articles  on  homoeomorphism  of  minerals 
(17,  85,  86,  210,  430;  18,  35,  131,  1854) ;  on  a  connection 
between  crystalline  form  and  chemical  constitution,  with 
some  inferences  therefrom  (44,  89,  252,  398, 1867). 


276  A  CENTURY  OF  SCIENCE 

A  great  many  new  mineral  names  were  proposed 
between  1850  and  1870,  a  large  number  of  which  have  con- 
tinued to  be  well-recognized  species.  But  there  was 
also  a  tendency,  which  has  not  wholly  disappeared  even 
now,  to  base  a  mineral  determination  upon  insufficient 
evidence,  and  to  propose  a  new  species  with  but  little 
justification  for  it.  In  this  connection  a  quotation  from 
the  introduction  by  J.  D.  Dana  to  the  3rd  Supplement  to 
the  System  of  Mineralogy  (4th  edition)  published  in  the 
Journal  (22,  page  246,  1856),  will  be  of  interest.  He 
says: 

*'Tt  is  a  matter  of  regret,  that  mineral  species  are  so  often 
brought  out,  especially  in  this  country,  without  sufficient  inves- 
tigation and  full  description.  It  is  not  meeting  the  just 
demands  of  the  science  of  mineralogy  to  say  that  a  mineral  has 
probably  certain  constituents,  or  to  state  the  composition  in  a 
general  way  without  a  complete  and  detailed  analysis,  especially 
when  there  are  no  crystallographic  characters  to  afford  the 
species  a  good  foundation.  We  have  a  right  to  demand  that 
those  who  name  species,  should  use  all  the  means  the  science  of 
the  age  admits  of,  to  prove  that  the  species  is  one  that  nature 
will  own,  for  only  such  belong  to  science,  and  if  enough  of  the 
material  has  not  been  found  for  a  good  description  there  is  not 
enough  to  authorize  the  introduction  of  a  new  name  in  the 
science.  The  publication  of  factitious  species,  in  whatever 
department  of  science,  is  progress  not  towards  truth,  but  into 
regions  of  error;  and  often  much  and  long  labor  is  required 
before  the  science  recovers  from  these  backward  steps. ' ' 

J.  Lawrence  Smith  was  born  in  1818  and  died  in  1883. 
He  was  a  graduate  of  the  University  of  Virginia  and  of 
the  Medical  College  of  Charleston  and  later  spent  three 
years  studying  in  Paris.  Shortly  after  the  completion 
of  his  studies  he  went  to  Turkey  as  an  advisor  to  the 
government  of  that  country  in  connection  with  the  grow- 
ing of  cotton  there.  During  this  time  he  investigated  the 
emery  mines  of  Asia  Minor,  and  wrote  a  memoir  upon 
them  which  was  later  published  by  the  French  Academy. 
He  served  as  professor  of  chemistry  in  the  University  of 
Virginia  and  later  held  the  same  chair  in  the  University 
of  Illinois.  He  published  a  long  series  of  papers  on  the 
chemical  composition  of  minerals  and  meteorites,  as  well 
as  on  pure  chemical  subjects.     Among  the  more  notable 


J'u>9k'JD 


GROWTH  OF  MINERALOGY  277 

of  his  contributions  are  the  ** Memoir  on  Emery"  (1850), 
a  series  of  papers  on  the  *  ^  Reexamination  of  American 
Minerals''  (1853)  written  with  the  collaboration  of 
George  J.  Brush,  and  his  *^ Memoir  on  Meteorites'' 
(1855). 

George  J.  Brush  entered  on  his  scientific  career  at  the 
moment  when  science  and  scientific  methods  of  research 
were  just  beginning  to  be  appreciated  in  this  country, 
and  he  soon  became  one  of  the  leading  pioneers  in  the 
movement.  While  his  half  century  of  active  service  was 
largely  occupied  by  administrative  duties  in  connection 
with  the  Sheffield  Scientific  School,  his  interest  in  min- 
eralogy never  flagged.  His  papers  on  mineralogical  sub- 
jects number  about  thirty,  all  of  which  were  published  in 
the  Journal.  These  began  in  1849,  even  before  his 
graduation  from  college,  and  continued  until  his  last 
paper  (in  collaboration  with  S.  L.  Penfield)  appeared  in 
1883.  Three  of  the  early  papers  were  written  with 
J.  Lawrence  Smith  as  noted  above.  These  papers  first  set 
in  this  country  the  standard  for  thorough  and  accurate 
scientific  mineral  investigation.  Later  in  life  he  was 
active  in  the  development  of  the  remarkable  mineral 
locality  at  Branchville,  Conn.,  and,  with  the  collaboration 
of  E.  S.  Dana,  published  in  the  Journal  (1878-90)  five 
important  articles  on  its  minerals.  This  locality,  with  the 
exception  of  the  zinc  deposits  at  Franklin  Furnace,  N.  J., 
was  the  most  remarkable  yet  discovered  in  this  country. 
Nearly  forty  different  mineral  species  were  found  there, 
of  which  nine  (mostly  phosphates)  were  new  to  science. 
There  has  certainly  been  no  other  series  of  descriptive 
papers  on  a  mineralogical  locality  of  equal  importance 
published  in  this  country. 

In  addition  to  publishing  original  papers,  Brush  did 
considerable  editorial  work  in  connection  with  the  fourth 
(1854)  and  fifth  (1868)  editions  of  the  System  of  Miner- 
alogy and  the  Appendices  to  them.  His  Manual  of 
Determinative  Mineralogy,  with  a  series  of  determinative 
tables  adapted  from  similar  ones  by  von  Kobell,  was  first 
published  in  1874.  It  was  revised  in  1878  and  later 
rewritten  by  S.  L.  Penfield.  This  book  did  much  to  make 
possible  the  rapid  and  accurate  determination  of  mineral 
species.     Throughout  his  life.  Brush  was  an  enthusiastic 


278  A  CENTURY  OF  SCIENCE 

collector  of  minerals,  building  up  the  notable  collection 
that  now  bears  his  name.  Perhaps,  however,  his  most 
important  contribution  to  the  development  of  mineralogy 
in  America  lay  rather  in  his  influence  upon  his  many 
students.  With  his  enthusiasm  for  accurate  and  pains- 
taking investigation  he  was  an  inspiration  to  all  who 
came  in  contact  with  him  and  his  own  field  and  science 
in  general  owes  much  to  that  influence. 

Among  the  early  mineralogists  in  this  country,  who 
were  concerned  in  the  chemical  analyses  of  minerals, 
none  accomplished  more  or  better  work  than  Frederick 
A.  Genth.  He  was  born  in  Germany  in  1820  and  lived 
in  that  country  until  1848,  when  he  came  to  the  United 
States  and  settled  in  Philadelphia.  He  had  studied  in 
various  German  universities  and  worked  under  some  of 
the  most  famous  chemists  of  that  time.  His  papers  in 
mineralogy  number  more  than  seventy-five,  in  the  great 
majority  of  which  chemical  analyses  are  given.  He  pub- 
lished fifty-four  successive  articles,  the  greater  part  of 
which  appeared  in  the  Journal,  which  were  entitled  Con- 
tributions to  Mineralogy.  In  these  he  gave  descriptions 
of  more  than  two  hundred  different  minerals,  most  of 
which  were  accompanied  by  analyses.  He  described 
more  than  a  dozen  new  and  well-established  mineral  spe- 
cies. He  was  especially  interested  in  the  rarer  elements 
and  many  of  his  analyses  were  of  minerals  containing 
them.  Especially  interesting  was  his  work  with  the  tel- 
lurides,  the  species  coloradoite,  melonite  and  calaverite 
being  first  described  by  him.  A  long  and  important 
investigation  was  recorded  on  Corundum,  **Its  Altera- 
tions and  Associate  Minerals,"  published  in  the  Pro- 
ceedings of  the  American  Philosophical  Society  in  1873 
(13,361).    Dr.  Genth  died  in  1893. 

The  period  from  1860  until  1875  was  not  very  produc- 
tive in  mineralogical  investigations.  The  first  ten  vol- 
umes of  the  Third  Series  of  the  Journal,  covering  the 
years  1871-1876,  contained  mineralogical  articles  by  only 
some  fifteen  different  authors.  But  from  that  time  on, 
the  amount  of  work  done  and  the  number  of  investigators 
grew  rapidly.  With  this  increase  in  activity  came  also 
a  decided  change  in  the  character  of  the  work.  The 
period  between  1871  and  1895  can  be  characterized  as  one 


GROWTH  OF  MINERALOGY  279 

in  which  all  the  various  aspects  of  mineral  investigation 
received  more  nearly  equal  prominence.  While  the 
chemical  composition  of  minerals  still  held  rightly  its 
prominent  place,  the  investigation  of  the  crystallographic 
and  optical  characters  and  the  relationships  existing 
between  all  three  were  of  much  more  frequent  occurrence. 
Edward  S.  Dana  commenced  his  scientific  work  by  pub- 
lishing in  1872  an  article  on  the  crystals  of  datolite  which 
was  probably  the  first  American  article  concerned  wholly 
with  the  description  of  the  crystallography  of  a  mineral. 
Samuel  L.  Penfield  began  his  important  investigations  in 
1877  and  the  first  articles  by  Frank  W.  Clarke  appeared 
during  this  period.  The  first  edition  of  the  Text  Book 
of  Mineralogy  by  Edward  S.  Dana  with  its  important 
chapters  on  Crystallography  and  Optical  Mineralogy 
was  published  in  1877  and  his  revision  of  the  System  of 
Mineralogy  (sixth  edition)  appeared  in  1892. 

Unquestionably  the  foremost  figure  in  American  min- 
eralogy during  this  period  was  that  of  Samuel  L.  Pen- 
field.  He  embodied  in  an  unusual  degree  the  characters 
making  for  success  in  this  science,  for  few  investigators 
in  mineralogy  have  shown,  as  he  did,  equal  facility  in  all 
branches  of  descriptive  mineralogy.  He  was  a  skilled 
chemist  and  possessed  in  a  high  degree  that  ingenuity  in 
manipulation  so  necessary  to  a  great  analyst.  He  was 
also  an  accurate  and  resourceful  crystallographer  and 
optical  mineralogist.  His  contributions  to  the  science  of 
mineralogy  can  be  partially  judged  by  the  following 
brief  summary  of  his  work.  He  published  over  eighty 
mineralogical  papers,  practically  all  of  which  were 
printed  in  the  Journal.  These  included  the  descriptions 
of  fourteen  new  mineral  species,  the  establishment  of  the 
chemical  composition  of  more  than  twenty  others,  and 
the  crystallization  of  about  a  dozen  more.  By  a  series 
of  brilliant  investigations  he  established  the  isomorphism 
between  fluorine  and  the  hydroxyl  radical.  He  first 
enunciated  the  theory  that  the  crystalline  form  of  a  min- 
eral was  due  to  the  mass  effect  of  the  acid  present  rather 
than  that  of  the  bases.  He  contributed  also  a  number  of 
articles  on  the  stereographic  projection  and  its  use  in 
crystallographic  investigations,  devising  a  series  of  pro- 
tractors and  scales  to  make  possible  the  rapid  and  accu- 


280  A  CENTURY  OF  SCIENCE 

rate  use  of  this  projection  in  solving  problems  in 
crystallography. 

Penfield  was  born  in  1856,  was  graduated  from  the 
Sheffield  Scientific  School  in  1877  and  immediately 
became  an  assistant  in  the  chemical  laboratory  of  that 
institution.  At  this  time  he,  together  with  his  colleague 
Horace  L.  Wells,  made  the  analyses  of  the  minerals  from 
the  newly  discovered  Branchville  locality.  He  spent  the 
years  1880  and  1881  in  studying  chemistry  in  Germany, 
returning  to  Yale  as  an  instructor  in  mineralogy  in  the 
fall  of  1881.  Except  for  another  semester  in  Europe  at 
Heidelberg  he  continued  as  instructor  and  professor  of 
mineralogy  in  the  Sheffield  Scientific  School  until  his 
early  death  in  1906. 

It  is  difficult  to  choose  for  mention  the  names  of  other 
investigators  in  Mineralogy  during  this  period.  Toward 
its  end  a  great  many  writers  contributed  to  the  pages  of 
the  Journal,  more  than  fifty  different  names  being 
counted  for  the  volumes  41  to  50  of  the  Third  Series. 
Many  of  these  are  still  living  and  still  active  in  scientific 
research.  Mention  should  be  made  of  Frank  W.  Clarke, 
who  contributed  many  important  articles  concerning 
the  chemical  constitution  of  the  silicates.  His  work  on 
the  mica  and  zeolite  groups  is  especially  noteworthy. 
The  work  of  W.  H.  Hillebrand,  particularly  in  regard  to 
his  analytical  investigations  of  the  minerals  containing 
the  rarer  elements,  was  of  great  importance.  The  name 
of  W.  E.  Hidden  should  be  remembered,  because,  with 
his  keen  and  discriminating  eye  and  active  search  for  new 
mineral  localities,  he  was  able  to  make  many  additions  to 
the  science. 

In  glancing  over  the  indices  to  the  Journal  the  close 
interrelation  of  mineralogy  to  the  other  sciences  is  strik- 
ingly shown  by  the  fact  that  so  many  scientists  whose 
particular  fields  are  along  other  lines  have  published 
occasional  mineralogical  papers.  Frequently  a  young 
man  has  commenced  with  mineralogical  investigations 
and  then  later  been  drawn  definitely  into  one  of  these 
allied  subjects.  Men,  who  have  won  their  reputation  in 
chemistry,  physics,  and  all  the  various  divisions  of  geol- 
ogy, even  that  of  palaeontology,  have  all  contributed  arti- 
cles   distinctly   mineralogical    in    character.      For    this 


GROWTH  OF  MINERALOGY  281 

reason  the  number  of  American  writers  who  have  pub- 
lished what  may  be  called  casual  papers  on  mineralogy 
is  very  great  in  comparison  to  the  number  of  those  who 
continue  such  publications  over  a  series  of  years. 

That  the  subject  of  meteorites  is  one  which  has  been 
constantly  studied  by  American  mineralogists  and  petrog- 
raphers  is  shown  by  the  long  list  of  papers  concerning  it 
that  have  been  published  in  the  Journal ;  it  should,  there- 
fore, be  considered  briefly  here.  Many  of  these  papers 
are  short  and  of  a  general  descriptive  nature  but  others 
which  give  more  fully  the  chemical,  mineralogical  and 
physical  details  are  numerous.  Among  the  earlier 
writers  on  this  subject  Benjamin  Silliman,  Jr.,  and  C.  TJ. 
Shepard  should  be  mentioned.  The  latter  was  the  first 
to  recognize  a  new  mineral  in  the  Bishopville  meteorite 
which  he  called  chladnite.  The  same  substance  was 
afterwards  found  in  a  terrestial  occurrence  and  was  more 
accurately  described  by  Kenngott  under  the  name  of 
enstatite.  J.  Lawrence  Smith  later  showed  that  these 
two  substances  were  identical.  Smith  did  a  large 
amount  of  important  chemical  work  on  meteorites.  He 
was  the  first  to  note  the  presence  of  ferrous  chloride  in 
meteoric  iron,  the  mineral  being  afterwards  named  law- 
rencite  in  his  honor.  The  iron-chronium  sulphide, 
daubreeiite,  was  also  first  described  by  him.  Other 
names  that  should  be  mentioned  in  this  connection  are 
those  of  A.  W.  Wright  who  studied  the  gaseous  con- 
stituents of  meteorites,  G.  F.  Kunz,  W.  E.  Hidden,  A.  E. 
Foote  and  H.  A.  Ward,  all  of  whom  published  numerous 
descriptions  of  these  iDodies.  Among  the  more  recent 
workers  in  this  field  the  names  of  G.  P.  Merrill  and  0.  C. 
Farrington  deserve  especial  mention. 

The  publication  of  the  Fourth  Series  of  the  Journal 
began  in  1896.  Although  the  years  since  then  have  seen 
a  great  amount  of  very  important  work  accomplished,  the 
history  of  the  period  is  fresh  in  the  minds  of  all  and  as 
the  majority  of  the  active  workers  are  still  living  and 
productive  it  seems  hardly  necessary  to  go  into  great 
detail  concerning  it.  Twenty  years  ago  it  seemed  to 
some  mineralogists  that  the  science  could  almost  be  con- 
sidered complete.  All  the  commoner  minerals  had  cer- 
tainly been  discovered  and  exhaustively  studied.    Little 


282  A  CENTUEY  OF  SCIENCE 

apparently  was  left  that  could  be  added  to  our  knowledge 
of  them.  New  occurrences  would  still  be  recorded,  new 
crystal  habits  would  be  observed,  and  an  occasional  new 
and  small  crystal  face  might  be  listed,  but  few  facts  of 
great  importance  seemed  undiscovered.  This  view  was 
not  wholly  justified  because  new  facts  of  interest  and 
importance  have  continuously  been  brought  forward,  and 
the  finding  of  new  minerals  does  not  appear  to  diminish 
in  amount  with  the  years.  The  work  of  the  investigators 
on  the  United  States  Geological  Survey  along  these  lines 
is  especially  noteworthy. 

This  last  of  our  periods,  however,  is  chiefly  signalized 
by  a  practically  new  development  along  the  lines  that 
might  be  characterized  as  experimental  mineralogy. 
New  ways  have  been  discovered  in  which  to  study  min- 
erals. The  important  but  hitherto  baffling  problems  of 
their  genesis,  together  with  their  relations  to  their 
surroundings,  and  to  associated  minerals,  have  been 
attacked  by  novel  methods. 

In  this  pioneer  work  that  of  the  Geophysical  Labora- 
tory of  the  Carnegie  Institution  of  Washington  has  been 
of  the  greatest  importance.  This  laboratory  was  estab- 
lished in  1905  and,  under  the  directorship  of  Arthur  L. 
Day,  a  notable  corps  of  investigators  has  been  assembled 
and  remarkable  work  already  accomplished.  While  the 
field  of  investigation  of  the  laboratory  is  broader  than 
that  of  mineralogy,  including  much  that  belongs  to 
petrography,  vulcanology,  etc.,  still  the  greater  part  of 
the  work  done  can  be  properly  classed  as  mineralogical  in 
character  and  should  be  considered  here.  Because  of  its 
great  value,  however,  it  was  felt  that  an  authoritative, 
although  necessarily,  under  existing  conditions,  a  brief, 
account  of  it  should  be  given.  A  concise  summary  of  the 
objects,  methods  and  results  of  the  investigations  of  the 
laboratory  has  been  kindly  prepared  by  a  member  of  its 
staff,  Dr.  R.  B.  Sosman,  and  is  given  later. 

During  the  last  few  years  another  line  of  investigation 
has  been  opened  by  the  discovery  of  the  effect  of  crystal- 
line structure  upon  X-rays.  Through  the  refraction  or 
reflection  of  the  X-ray  by  means  of  the  ordered  arrange- 
ment of  the  particles  forming  the  crystalline  network,  we 
are  apparently  going  to  be  able  to  discover  much  con- 


GROWTH  OF  MINERALOGY  283 

cerning  the  internal  structure  of  crystals.  And,  partly 
through  these  discoveries,  is  likely  to  come  in  turn  the 
solution  of  the  hitherto  insolvable  mystery  of  the  consti- 
tution of  matter.  Without  doubt  the  multitudinous  facts 
of  mineralogy  assembled  during  the  past  century  by  the 
painstaking  investigation  of  a  large  number  of  scientists 
are  destined  to  play  a  large  part  in  the  solution  of  this 
problem.  Further,  it  does  not  seem  too  bold  a  prophecy 
to  suggest,  that  the  time  will  come  when  it  will  be  possi- 
ble to  assemble  all  these  unorganized  facts  that  we  know 
about  minerals  into  a  harmonious  whole  and  that  we  shall 
be  then  able  to  formulate  the  underlying  and  fundamental 
principles  upon  which  they  all  depend.  These  are  the 
great  problems  for  the  future  of  mineralogical  inves- 
tigation. 


IX 

THE  WORK  OF  THE  GEOPHYSICAL.  LABOR- 
ATORY OF  THE  CARXEGIE  Il^STITUTION 
OF   WASHINGTON 

By  R.  B.  SOSMAN 

THERE  are  three  methods  of  approach  to  the  great 
problem  of  rock  formation.  The  first  undertakes  to 
reproduce  by  suitable  laboratory  experiments  some 
of  the  observed  changes  in  natural  rocks.  The  second 
seeks  to  apply  the  principles  of  physical  chemistry  to  a 
great  body  of  carefully  gathered  statistics.  The  third 
method  of  attack  is  like  the  first  in  being  a  laboratory 
method,  and  like  the  second  in  seeking  to  apply  existing 
knowledge  to  the  association  of  minerals  as  found  in 
rocks,  but  in  its  procedure  differs  widely  from  both.  It 
consists  of  bringing  together  pure  materials  under 
measurable  conditions,  and  thus  in  establishing  by 
strictly  quantitative  methods  the  relations  in  which  min- 
erals can  exist  together  under  the  conditions  of  tempera- 
ture and  pressure  that  have  the  power  to  aifect  such 
relations. 

It  is  to  this  third  method  of  investigation  of  the  prob- 
lems of  the  rocks  that  the  Geophysical  Laboratory  has 
iDeen  devoted  since  its  establishment  in  1905.  It  has 
proved  entirely  practicable  to  make  quantitative  studies 
of  the  relations  among  the  principal  earth-forming 
oxides  (silica,  alumina,  magnesia,  lime,  soda,  potash,  and 
the  oxides  of  iron)  over  a  very  wide  range  of  tempera- 
tures. The  resources  of  physics  have  proved  adequate 
to  establish  temperature  with  a  high  degree  of  precision 
and  to  measure  the  quantity  of  energy  involved  in  the 
various  reactions.  The  chemist  has  been  able  to  obtain 
materials  in  a  high  degree  of  purity,  and  to  follow  out  in 
detail  the  chemical  relationships  that  exist  among  the 


GEOPHYSICAL  LABORATORY  285 

earth-forming  oxides.  The  petrographic  laboratory  has 
been  available  for  the  comparison  of  synthetic  laboratory 
products  with  the  corresponding  natural  minerals. 

It  has  also  proved  entirely  practicable  to  extend  the 
same  methods  of  research  to  some  of  the  principal  ore 
minerals  such  as  the  sulphides  of  copper.  Other  infor- 
mation which  is  certain  to  be  of  ultimate  economic  value 
has  also  come  out  of  the  thorough  study  of  the  silicates, 
which  are  basic  materials  for  the  vast  variety  of  indus- 
tries which  are  classed  under  the  name  of  ceramic  indus- 
tries. The  best  example  of  this  is  the  facility  with  which 
the  experience  and  the  personnel  of  the  laboratory  has 
been  adapted  to  the  very  important  problem  of  manufac- 
turing an  adequate  supply  of  optical  glass  for  the  needs 
of  the  United  States  in  the  present  war. 

It  has  further  been  possible  to  show  within  the  last  two 
years  that  rock  formation  in  which  volatile  ingredients 
play  a  necessary  and  determining  part  can  be  completely 
studied  in  the  laboratory  with  as  much  precision  as 
though  all  the  components  were  solids  or  liquids. 

Along  with  the  laboratory  work  on  the  formation  of 
minerals  and  rocks  has  gone  an  increasing  amount  of  field 
work  on  the  activities  of  accessible  volcanoes,  such  as 
Kilauea  and  Vesuvius,  where  the  fusion  and  recrystal- 
lization  of  rocks  on  a  large  scale  can  be  observed  and 
studied. 

There  was  once  a  time  when  the  confidence  of  the  lab- 
oratory in  the  capacity  of  physics  and  chemistry  to  solve 
geological  problems  was  not  shared  by  all  geologists. 
There  were  some  who  were  inclined  to  view  with  consid- 
erable apprehension  the  vast  ramifications  and  com- 
plications of  natural  rock  formation  as  a  problem 
impossible  of  adequate  solution  in  the  laboratory.  It  is, 
therefore,  a  matter  of  satisfaction  to  all  those  who  have 
participated  in  these  efforts  to  see  the  evidences  of  this 
apprehension  disappearing  gradually  as  the  work  has 
progressed.  A  careful  appraisement  of  the  situation 
to-day,  after  ten  years  of  activity,  reveals  the  fact  that 
the  tangible  grounds  for  anxiety  about  the  accessibility 
of  the  problems  which  were  confronted  at  first  are  now 
for  the  most  part  dissipated. 

It  will  not  be  possible  to  review  in  detail  the  lines  of 

18 


286  A  CENTURY  OF  SCIENCE 

work  sketched  above.  An  outline  of  the  synthetic  work 
on  systems  of  the  mineral  oxides  and  a  paragraph  on  the 
volcano  researches  will  perhaps  suffice  to  indicate  the 
general  plan  and  purpose  of  the  laboratory's  work.  It 
should  be  added  that  the  results  of  many  of  the  researches 
of  the  laboratory,  detailed  below,  have  been  published  in 
the  pages  of  the  Journal  (see  21,  89,  1906,  and  later 
volumes). 

Mineral  Researches. — The  mineral  studies  include : 

I.  One-component  systems:  silica,  with  its  numerous 
polymorphic  forms  and  their  relations  to  temperature 
and  the  conditions  of  rock  formation;  alumina;  mag- 
nesia ;  and  lime. 

II.  Two-component  systems:  silica-alumina,  includ- 
ing sillimanite  and  related  minerals;  silica-magnesia, 
including  the  tetramorphic  metasilicate  MgSiOg ;  silica- 
lime,  including  wollastonite ;  the  alkali  silicates,  par- 
ticularly with  reference  to  their  equilibria  with  carbon 
dioxide  and  with  water ;  ferric  oxide-lime ;  alumina-lime ; 
alumina-magnesia,  including  spinel;  and  hematite-mag- 
netite, a  solid-solution  series  of  an  unusual  type. 

III.  Three-component  systems:  silica-alumina-mag- 
nesia,  completed  but  not  yet  published;  silica-alumina- 
lime,  complete,  including  the  compounds  that  enter  into 
the  composition  of  portland  cement;  silica-magnesia- 
lime,  completed  but  not  yet  published,  including,  however, 
published  work  on  the  diopside-forsterite-silica  system, 
and  on  the  CaSiOg-MgSiOg  series;  and  alumina-mag- 
nesia-lime. 

IV.  Four  components:  SiOg-AlgOg-MgO-CaO :  the  in- 
complete system  anorthite-f orsterite-silica ;  SiOs-AlgOg- 
CaO-NaaO:  the  series  of  lime-soda  feldspars  (albite- 
anorthite),  and  the  series  nephelite  (carnegieite)-anor- 
thite;  SiOg-AlgOg-NaaO-KsO:  the  sodium- potassium 
nephelites. 

V.  Five  components:  SiOg-AlaOg-MgO-CaO-NagO: 
the  ternary  system  diopside-anorthite-albite  (haplo-basal- 
tic  and  haplo-dioritic  magmas). 

Fairly  complete  studies  have  also  been  made  of  the 
mineral  sulphides  of  iron,  copper,  zinc,  cadmium,  and 
mercury,  and  the  conditions  controlling  the  secondary 
enrichment  of  copper  sulphide  ores  are  now  being  inves- 


GEOPHYSICAL  LABORATORY  287 

tigated.  In  connection  with  the  sulphide  investigations, 
the  hydrated  oxides  of  iron  have  been  studied  chemically 
and  microscopically  and  the  results  will  soon  be  ready  for 
publication. 

Throughout  the  work  the  mere  accumulation  of  bodies 
of  facts  has  been  held  to  be  secondary  in  importance  to 
the  development  of  new  methods  of  attack  and  the  eval- 
uation of  new  general  principles,  and  the  specific  prob- 
lems studied  have  been  selected  from  this  point  of  view. 

Volcano  Researches. — A  branch  of  the  laboratory's 
work  that  is  of  general  as  well  as  petrological  interest 
is  the  study  of  active  volcanoes.  Observations  and  col- 
lections have  been  made  at  Kilauea,  Vesuvius,  Etna, 
Stromboli,  Vulcano,  and  (through  the  courtesy  of  the 
directors  of  the  National  Geographic  Society)  Katmai  in 
Alaska.  The  great  importance  of  gases  in  volcanicity  is 
emphasized  by  all  the  studies.  The  active  gases  include 
hydrogen  and  water  vapor,  carbon  monoxide  and  carbon 
dioxide,  and  sulphur  and  its  oxides,  as  well  as  a  variety 
of  other  compounds  of  lesser  importance.  The  crater  of 
Kilauea  proves  to  be  an  active  natural  gas-furnace,  in 
which  reactions  are  continuously  occurring  among  the 
gases,  often  resulting  in  making  the  lava  basin  hotter  at 
the  surface  than  it  is  at  some  depth.  These  reactions 
are  being  studied  in  the  laboratory  on  mixtures  of  the 
pure  constituent  gases  in  known  proportions,  in  order  to 
lay  the  foundation  for  accurate  interpretation  and  pre- 
diction concerning  the  gases  as  actually  collected  from 
the  volcanoes  themselves. 


THE  PROGRESS  OF  CHEMISTRY  DURIIVG  THE 
PAST  ONE  HUNDRED  YEARS 

By  HORACE  L..  WELLS  and  HARRY  W.  FOOTE 

Introduction, 

AS  we  look  back  to  the  time  of  the  founding  of  the 

\  Journal  in  1818,  we  see  that  the  science  of  chem- 
JIJL.  istry  had  recently  made  and  was  then  making  great 
advances.  That  the  scientific  men  of  those  days  were 
much  impressed  with  what  was  being  accomplished  is  well 
shown  by  the  following  statement  made  in  an  early  num- 
ber of  the  Journal  (3,  330,  1821)  by  its  founder  in 
reviewing  Gorham's  Elements  of  Chemical  Science.  He 
says :  *  *  The  present  period  is  distinguished  by  wonderful 
mental  activity;  it  might  indeed  be  denominated  as  the 
intellectual  age  of  the  world.  At  no  former  period  has 
the  mind  of  man  been  directed  at  one  time  to  so  many  and 
so  useful  researches." 

A  very  remarkable  revolution  in  chemical  ideas  had 
recently  taken  place.  Soon  after  the  discovery  of  oxy- 
gen by  Priestley  in  1774,  and  the  subsequent  discovery 
by  Cavendish  that  water  was  formed  by  the  combustion 
of  hydrogen  and  oxygen,  Lavoisier  had  explained  com- 
bustion in  general  as  oxidation,  thus  overthrowing  the 
curious  old  phlogiston  theory  which  had  prevailed  as  the 
basis  of  chemical  philosophy  for  nearly  a  century. 

The  era  of  modern  chemistry  had  thus  begun,  and  the 
additional  views  that  matter  was  indestructible  and  that 
chemical  compounds  were  of  constant  composition  had 
been  generally  accepted  at  the  beginning  of  the  nine- 
teenth century. 

Dalton  had  announced  his  atomic  theory  in  1802,  hav- 
ing based  it  largely  upon  the  law  of  multiple  proportions 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    289 

which  he  had  previously  discovered,  and  he  had  begun 
to  express  the  formulas  for  compounds  in  terms  of 
atomic  symbols. 

In  1808  Gay-Lussac  had  discovered  his  law  of  gas  com- 
bination in  simple  proportions,^  a  law  of  supreme  import- 
ance in  connection  with  the  atomic  theory,  but  neither  he 
nor  Dalton  had  seen  this  theoretical  connection.  Avo- 
gadro  had  understood  it,  however,  and  in  1811  had 
reached  the  momentous  conclusion  that  all  gases  and 
vapors  have  equal  numbers  of  molecules  in  equal  volumes 
at  the  same  temperature  and  pressure. 

Davy  in  1807  had  isolated  the  alkali-metals,  sodium 
and  potassium,  by  means  of  electrolysis,  thus  practically 
dispelling  the  view  that  certain  earthy  substances  might 
be  elementary;  and  about  four  year s^ later  he  had  demon- 
strated that  chlorine  was  an  element,  not  an  oxide  as  had 
been  supposed  previously,  thus  overthrowing  Lavoisier's 
view  that  oxygen  was  the  characteristic  constituent  of  all 
acids. 

At  the  time  that  our  period  of  history  begins,  the 
atomic  theory  had  been  accepted  generally,  but  in  a  some- 
what indefinite  form,  since  little  attention  had  been  paid 
to  Avogadro  's  principle,  and  since  Dalton  had  used  only 
the  principle  of  greatest  simplicity  in  writing  the  formu- 
las of  compounds,  considering  water  as  HO  and  ammonia 
NH,  for  example.  At  this  time,  however,  Berzelius  for 
ten  or  fifteen  years  had  been  devoting  tremendous  energy 
to  the  task  of  determining  the  atomic  weights  of  nearly 
all  of  the  elements  then  known  by  analyzing  their 
compounds.  He  had  confirmed  the  law  of  multiple  pro- 
portions, accepted  the  atomic  theory,  and  utilized  Avo- 
gadro's  principle,  and  it  is  an  interesting  coincidence 
that  his  first  table  of  atomic  weights  was  published  in  the 
year  1818. 

An  interesting  account  of  the  views  on  chemistry  held 
at  about  that  time  was  published  in  the  Journal  by  Deni- 
son  Olmsted  (11,  349,  1826;  12,  1,  1827),  who  had 
recently  become  professor  of  natural  philosophy  in  Yale 
College. 

The  most  illustrious  European  chemists  of  that  time 
were  Berzelius  of  Sweden,  Davy  of  England,  and  Gay- 
Lussac  of  France,  and  the  curious  circumstance  may  be 


290  A  CENTURY  OF  SCIENCE 

mentioned  that  all  three  of  them  and  also  Benjamin  Silli- 
man,  the  founder  of  the  Journal,  were  born  within  a 
period  of  eight  months  in  1778-1779. 

In  this  country  Robert  Hare  of  Philadelphia  and  Ben- 
jamin Silliman  were  undoubtedly  the  most  prominent 
chemists  of  those  days.  Hare  is  best  known  for  his 
invention  of  the  compound  blowpipe,  but  his  contribu- 
tions to  the  Journal  were  very  numerous,  beginning 
almost  with  the  first  volume  and  continuing  for  over 
thirty  years.  Among  the  first  of  these  contributions  was 
a  most  vigorous  but  well-merited  attack  upon  a  Doctor 
Clark  of  Cambridge,  England,  who  had  copied  his  inven- 
tion without  giving  him  proper  credit.  He  begins  (2, 
281,  1820)  by  saying:  ^^Dr.  Clark  has  published  a  book 
on  the  gas  blowpipe  in  which  he  professes  a  sincere  desire 
to  render  everyone  his  due.  That  it  would  be  difficult  for 
the  conduct  of  any  author  to  be  more  discordant  with 
these  professions,  I  pledge  myself  to  prove  in  the  fol- 
lowing pages. ' ' 

Hare  also  invented  a  galvanic  battery  which  he  called 
a  '^deflagrator,"  consisting  of  a  large  number  of  single 
cells  in  series.  With  this,  using  carbon  electrodes,  he 
was  able  to  obtain  a  higher  temperature  than  with  his 
oxy-hydrogen  blowpipe.  He  was  the  first  to  apply  gal- 
vanic ignition  to  blasting  (21,  139,  1832),  and  he  first 
carried  out  electrolyses  with  the  use  of  mercury  as  the 
cathode  (37,  267,  1839).  In  this  way  he  prepared 
metallic  calcium  and  other  metals  from  solutions  of  their 
chlorides,  while  the  principle  employed  by  him  has  in 
recent  times  been  used  as  the  basis  of  a  very  important 
process  for  manufacturing  caustic  potash  and  soda. 

Silliman,  who  had  become  an  intimate  friend  of  Hare 
during  two  periods  of  chemical  study  under  Woodhouse 
in  Philadelphia  in  1802-1804,  and  who  soon  afterwards 
spent  fourteen  months  as  a  student  abroad,  chiefly  in 
England  and  Scotland,  took  a  broad  interest  in  science 
and  gave  much  attention  to  geology  as  well  as  to  chem- 
istry. In  spite  of  this  divided  interest  and  his  work  as 
a  teacher,  popular  scientific  lecturer,  and  editor,  he  found 
time  for  a  surprising  amount  of  original  chemical  work. 
For  instance,  using  Hare's  deflagrator,  he  showed  that 
carbon  was  volatilized  in  the  electric  arc  (5,  108,  1822) ; 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    291 

he  was  the  first  in  this  country  to  prepare  hydrofluoric 
acid  (6,  354, 1823),  and  he  first  detected  bromine  in  one  of 
our  natural  brines  (18, 142, 1830). 


Atomic  Weights, 

As  soon  as  the  atomic  theory  was  accepted,  the  relative 
weights  of  the  atoms  became  a  matter  of  vital  importance 
in  connection  with  formulas  and  chemical  calculations. 
In  advancing  his  theory,  Dalton  had  made  some  very 
rough  atomic  weight  determinations,  and  it  has  been  men- 
tioned already  that  Berzelius,  at  the  time  that  our  histor- 
ical period  begins,  was  engaged  in  the  prodigious  task  of 
accurately  determining  these  constants  for  nearly  all  the 
known  elements.  It  is  recorded  that  he  analyzed  quan- 
titatively no  less  than  two  thousand  compounds  in 
connection  with  this  work  during  his  career.  His  table 
of  1818  has  proved  to  be  remarkably  accurate  for  that 
pioneer  period,  and  it  indicates  his  remarkable  skill  as  an 
analyst. 

It  is  to  be  observed  that  Berzelius  in  this  early  table 
made  use  of  Avogadro's  principle  in  connection  with 
elements  forming  gaseous  compounds,  and  thus  obtained 
correct  formulas  and  atomic  weights  in  such  cases,  but 
that  in  many  instances  his  atomic  weights  and  those  now 
accepted  bear  the  relation  of  simple  multiples  to  one 
another,  because  he  had  then  no  means  of  deciding  upon 
the  formulas  of  many  compounds  except  the  rule  of 
assumed  simplicity.  For  example,  the  two  oxides  of 
iron  now  considered  to  be  FeO  and  FeaOg  he  regarded  as 
FeOg  and  Fe03,  knowing  as  he  did  that  the  ratio  of 
oxygen  in  them  was  2  to  3,  and  believing  that  a  single 
atom  of  iron  in  each  was  the  simplest  view  of  the  case, 
so  that  as  the  consequence  of  these  formulas  the  atomic 
weight  of  iron  was  then  considered  to  be  practically 
twice  as  great  in  its  relation  to  oxygen  as  at  present. 

These  old  atomic  weights  of  Berzelius,  used  with  the 
corresponding  formulas,  were  just  as  serviceable  for  cal- 
culating compositions  and  analytical  factors  as  though 
the  correct  multiples  had  been  selected.  As  time  went 
on,  the  true  multiples  were  gradually  found  from  consid- 
erations of  atomic  heats,  isomorphism,  vapor  densities, 


292  A  CENTURY  OF  SCIENCE 

the  periodic  law,  and  so  on,  and  suitable  changes  were 
made  in  the  chemical  formulas. 

Berzelius  used  100  parts  of  oxygen  as  the  basis  of  his 
atomic  weights,  a  practice  which  was  generally  followed 
for  several  decades.  Dalton,  however,  had  originally 
used  hydrogen  as  unity  as  the  basis,  and  this  plan  finally 
came  into  use  everywhere,  as  it  seemed  to  be  more  log- 
ical and  convenient,  because  hydrogen  has  the  smallest 
atomic  weight,  and  also  because  the  atomic  weights  of  a 
number  of  common  elements  appeared  to  be  exact  multi- 
ples of  that  of  hydrogen,  thus  giving  simpler  numbers  for 
use  in  calculations. 

Within  a  few  years  a  slight  change  has  been  made  by 
the  adoption  of  oxygen  as  exactly  16  as  the  basis,  which 
gives  hydrogen  the  value  of  1-008. 

As  early  as  1815,  Prout,  an  English  physician,  had 
advanced  the  view  that  hydrogen  is  the  primordial  sub- 
stance of  all  the  elements,  and  consequently  that  the 
atomic  weights  are  all  exact  multiples  of  that  of  hydro- 
gen. This  hypothesis  has  been  one  of  the  incentives  to 
investigations  upon  atomic  weights,  for  it  has  been  found 
that  these  constants  in  the  cases  of  a  considerable  num- 
ber of  the  elements  are  very  close  to  whole  numbers 
when  based  upon  hydrogen  as  unity,  or  even  still  closer 
when  based  upon  oxygen  as  16. 

With  our  present  knowledge  Front's  hypothesis  may 
be  regarded  as  disproved  for  nearly  all  the  elements 
whose  atomic  weights  have  been  accurately  determined, 
but  the  close  or  even  exact  agreement  with  it  in  a  few 
cases  is  still  worthy  of  consideration.  There  is  an  inter- 
esting letter  from  Berzelius  to  B.  Silliman,  Jr.,  in  the 
Journal  (48,  369,  1845)  in  which  Berzelius  considers  the 
theory  entirely  disproved. 

For  a  long  time  entire  reliance  was  placed  upon  the 
atomic  weights  obtained  by  Berzelius,  but  it  came  to  be 
observed  that  the  calculation  of  carbon  from  carbon  diox- 
ide appeared  to  give  high  results  in  certain  cases,  so  that 
doubt  arose  as  to  the  accuracy  of  Berzelius 's  work.  Con- 
sequently in  1840  Dumas,  assisted  by  his  pupil  Stas,  made 
a  new  determination  of  the  atomic  weight  of  carbon,  and 
found  that  the  number  obtained  by  Berzelius,  12-12,  was 
slightly    too    large.     Subsequently    Dumas    determined 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    293 

more  than  twenty  other  atomic  weights,  but  this  great 
amount  of  work  did  not  bring  about  any  considerable 
improvement,  for  it  appears  that  Dumas  did  not  greatly 
excel  Berzelius  in  accuracy,  and  that  the  latter  had  made 
one  of  his  most  noticeable  errors  in  connection  with 
carbon. 

Soon  after  assisting  Dumas  in  the  work  upon  carbon, 
Stas  began  his  very  extensive  and  accurate,  independent 
determinations,  leading  to  the  publication  of  a  book  in 
1867  describing  his  work.  Stas  made  many  improve- 
ments in  methods  by  the  use  of  great  care  in  purifying 
the  substances  employed,  and  especially  by  using  large 
quantities  of  material  in  his  determinations,  thus  dimin- 
ishing the  proportional  errors  in  weighing.  His  results, 
which  dealt  with  most  of  the  common  elements,  were 
accepted  with  much  confidence  by  chemists  everywhere. 

Stas  reached  the  conclusion  that  there  could  be  no  real 
foundation  for  Front's  hypothesis,  since  so  many  of  his 
atomic  weights  varied  from  whole  numbers,  and  this 
opinion  has  been  generally  accepted. 

The  first  accurate  atomic  weight  determination  pub- 
lished in  the  Journal  was  that  by  Mallett  on  lithium  (22, 
349, 1856;  28,  349,  1859),  showing  a  result  almost  identi- 
cal with  that  accepted  at  the  present  time.  Johnson  and 
Allen's  determination  (35,  94,  1863)  on  the  rare  element 
caesium  was  carried  out  with  extraordinary  accuracy. 
Lee,  working  with  Wolcott  Gibbs,  made  good  determina- 
tions on  nickel  and  cobalt  (2,  44,  1871).  The  work  of 
Cooke  on  antimony  (15,  41,  107,  1878)  was  excellent. 

Concerning  the  more  recent  work  published  elsewhere 
than  in  the  Journal,  attention  should  be  called  particu- 
larly to  the  investigations  that  have  been  carried  on  for 
the  past  twenty-five  years  by  Richards  and  his  associates 
at  Harvard  University.  Richards  has  shown  masterly 
ability  in  the  selection  of  methods  and  in  avoiding  errors. 
His  results  have  displayed  such  marvelous  agreements 
among  repeated  determinations  by  the  same  and  by  dif- 
ferent processes  as  to  inspire  the  greatest  confidence. 
His  work  has  been  very  extensive,  and  it  is  a  great  credit 
to  our  country  that  this  atomic  weight  work,  so  superior 
to  all  that  has  been  previously  done,  is  being  carried 
out  here. 


294  A  CENTURY  OF  SCIENCE 

It  may  be  mentioned  that  for  a  number  of  years  the 
decision  in  regard  to  the  atomic  weights  to  be  accepted 
has  been  in  the  hands  of  an  International  Committee  of 
which  our  fellow  countryman  F.  W.  Clarke  has  been 
chairman.  In  connection  with  this  position  and  pre- 
viously, Clarke  has  done  valuable  service  in  re-calculat- 
ing and  summarizing  atomic  weight  determinations. 

Analytical  Chemistry, 

Analysis  is  of  such  fundamental  importance  in  nearly 
every  other  branch  of  chemical  investigation  that  its 
development  has  been  of  the  utmost  importance  in  con- 
nection with  the  advancement  of  the  science.  It  attained, 
therefore,  a  comparatively  early  development,  and  one 
hundred  years  ago  it  was  in  a  flourishing  condition,  par- 
ticularly as  far  as  inorganic  qualitative  and  gravimetric 
analysis  were  concerned.  There  is  no  doubt  that  Ber- 
zelius,  whose  atomic  weight  determinations  have  already 
been  mentioned,  surpassed  all  other  analysts  of  that  time 
in  the  amount,  variety,  and  accuracy  of  his  gravimetric 
work.  He  lived  through  three  decades  of  our  period, 
until  1848. 

During  the  past  century  there  has  been  constant  prog- 
ress in  inorganic  analysis,  due  to  improved  methods, 
better  apparatus  and  accumulated  experience.  An 
excellent  work  on  this  subject  was  published  by  H.  Rose, 
a  pupil  of  Berzelius,  and  the  methods  of  the  latter,  with 
many  improvements  and  additions  by  the  author  and 
others,  were  thus  made  accessible.  Fresenius,  who  was 
born  in  1818,  did  much  service  in  establishing  a  labora- 
tory in  which  the  teaching  of  analytical  chemistry  was 
made  a  specialty,  in  writing  text-books  on  the  subject 
and  in  establishing  in  1862  the  *  *  Zeitschrif  t  fiir  analy- 
tische  Chemie,''  which  has  continued  up  to  the  present 
time. 

Besides  Berzelius,  who  was  the  first  to  show  that  min- 
erals were  definite  chemical  compounds,  there  have  been 
many  prominent  mineral  analysts  in  Europe,  among 
whom  Rammelsberg  and  Bunsen  may  be  mentioned,  but 
there  came  a  time  towards  the  end  of  the  nineteenth  cen- 
tury when  the  attention  of  chemists,  particularly  in  Ger- 
many, was  so  much  absorbed  by  organic  chemistry  that 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    295 

mineral  analysis  came  near  becoming  a  lost  art  there. 
It  was  during  that  period  that  an  English  mineralogist, 
visiting  New  Haven  and  praising  the  mineral  analyses 
that  were  being  carried  out  at  Yale,  expressed  regret  that 
there  appeared  to  be  no  one  in  England,  or  in  Germany 
either,  who  could  analyze  minerals. 

The  best  analytical  work  done  in  this  country  in  the 
early  part  of  our  period  was  chiefly  in  connection  with 
mineral  analysis,  and  a  large  share  of  it  was  published  in 
the  Journal.  Henry  Seybert,  of  Philadelphia,  in  par- 
ticular, showed  remarkable  skill  in  this  direction,  and 
published  numerous  analyses  of  silicates  and  other  min- 
erals, beginning  in  1822.  It  was  he  who  first  detected 
boric  acid  in  tourmaline  (6,  155,  1822),  and  beryllium  in 
chrysoberyl  (8,  105,  1824).  His  methods  for  silicate 
analyses  were  very  similar  to  those  used  at  the  present 
time. 

J.  Lawrence  Smith  in  1853  described  his  method  for 
determining  alkalies  in  minerals  (16,  53),  a  method  which 
in  its  final  form  (1,  269, 1871)  is  the  best  ever  devised  for 
the  purpose.  He  also  described  (15,  94,  1853)  a  very 
useful  method,  still  largely  used  in  analytical  work,  for 
destroying  ammonium  salts  by  means  of  aqua  regia. 
Carey  Lea  (42,  109,  1866)  described  the  well-known  test 
for  iodides  by  means  of  potassium  dichromate.  P.  W. 
Clarke  (49,  48,  1870)  showed  that  antimony  and  arsenic 
could  be  quantitatively  separated  from  tin  by  the  pre- 
cipitation of  the  sulphides  in  the  presence  of  oxalic  acid. 
In  1864  Wolcott  Gibbs  (37,  346)  began  an  important 
series  of  analytical  notes  from  the  Lawrence  Scientific 
School,  and  he  worked  out  later  many  difficult  analytical 
problems,  particularly  in  connection  with  his  extensive 
researches  upon  the  complex  inorganic  acids. 

From  1850  on,  Brush  and  his  students  made  many 
important  investigations  upon  minerals,  and  from  1877 
Penfield  (13,  425),  beginning  with  an  analysis  of  a  new 
mineral  from  Branchville,  Connecticut,  described  by 
Brush  and  E.  S.  Dana,  displayed  remarkable  skill  and 
industry  in  this  kind  of  work.  Both  of  the  writers  of 
this  article  were  fortunate  in  being  associated  with  Pen- 
field  in  some  of  his  researches  upon  minerals  and  one  of 
us  bee:an  as  he  did  with  the  Branchville  work     It  is 


296  A  CENTURY  OF  SCIENCE 

probably  fair  to  say  that  Penfield  did  the  most  accurate 
work  in  mineral  analysis  that  has  ever  been  accom- 
plished, and  that  he  was  similarly  successful  in  crystal- 
lography and  other  physical  branches  of  mineralogy. 

The  American  analytical  investigations  that  have  been 
mentioned  were  all  published  in  the  Journal,  with  the 
exception  of  a  part  of  Gibbs's  work.  Many  other  Amer- 
ican workers  at  mineral  analysis  might  be  alluded  to 
here,  but  only  the  excellent  work  of  a  number  of  chemists 
in  the  United  States  Geological  Survey  will  be  mentioned. 
Among  these  Hillebrand  deserves  particular  praise  for 
the  extent  of  his  investigations  and  for  his  careful 
researches  in  improving  the  methods  of  rock  analysis. 

To  our  own  Professor  Gooch  especial  praise  must  be 
accorded  for  the  very  large  number  of  analytical  methods 
that  have  been  devised,  or  critically  studied,  by  him  and 
his  students,  and  for  the  excellent  quality  of  this  work. 
The  publications  in  the  Journal  from  his  laboratory 
began  in  1890  (39,  188),  and  the  extraordinary  extent  of 
this  work  is  shown  by  the  fact  that  the  three  hundredth 
paper  from  the  Kent  Laboratory  appeared  in  May,  1918. 
These  very  numerous  and  important  investigations  have 
been  of  great  scientific  and  practical  value,  and  they  have 
formed  a  striking  feature  of  the  Journal  for  nearly  30 
years.  In  1912  Gooch  published  his  **  Methods  in  Chem- 
ical Analysis,''  a  book  of  over  500  pages,  in  which  the 
work  in  the  Kent  Chemical  Laboratory  up  to  that  time 
was  concisely  presented.  Among  the  many  workers  who 
have  assisted  in  these  investigations,  P.  E.  Browning,  W. 
A.  Drushel,  F.  S.  Havens,  D.  A.  Kreider,  C.  A.  Peters,  L 
K.  Phelps  and  R.  G.  Van  Name  are  particularly  promi- 
nent. Besides  many  other  useful  pieces  of  apparatus, 
the  perforated  filtering  crucible  was  devised  by  Gooch, 
and  this  has  brought  hjs  name  into  everyday  use  in  all 
chemical  laboratories. 

Volumetric  analysis  was  originated  by  Gay-Lussac, 
who  described  a  method  for  chlorimetry  in  1824,  for 
alkalimetry  in  1828,  and  for  the  determination  of  silver 
and  chlorides  in  1832.  Margueritte  devised  titrations 
with  potassium  permanganate  in  1846,  while  Bunsen,  not 
far  from  the  same  time,  introduced  the  use  of  iodine  and 
sulphur  dioxide  solutions  for  the  purpose  of  determmmg 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    297 

many  oxidations  and  reductions.  We  owe  to  Mohr  some 
improvements  in  apparatus  and  a  German  text-book  on 
the  subject,  while  Sutton  wrote  an  excellent  English  work 
on  volumetric  analysis,  of  which  many  editions  have 
appeared. 

While  volumetric  analysis  began  to  be  used  less  than 
one  hundred  years  ago,  its  applications  have  been  grad- 
ually extended  to  a  very  great  degree,  and  it  is  not  only 
exceedingly  important  in  investigations  in  pure  chemis- 
try, but  its  use  is  especially  extensive  in  technical  labora- 
tories where  large  numbers  of  rapid  analyses  are 
required. 

Not  a  few  volumetric  methods  have  been  devised  or 
improved  in  the  United  States,  but  mention  will  be  made 
here  only  of  -  Cooke's  important  method  for  the  deter- 
mination of  ferrous  iron  in  insoluble  silicates,  published 
in  the  Journal  (44,  347,  1867)  ;^  to  Penfield's  method  for 
the  determination  of  fluorine  in  1878;  and  to  the  more 
recent  general  method  of  titration  with  an  iodate  in 
strong  hydrochloric  acid  solutions,  due  to  L.  W. 
Andrews,  a  number  of  applications  of  which  have  been 
worked  out  in  the  Sheffield  Laboratory. 

A  considerable  amount  of  work  with  gases  had  been 
done  by  Priestley,  Scheele,  Cavendish,  Lavoisier,  Dalton, 
Gay-Lussac,  and  others  before  our  hundred-year  period 
began.  Cavendish,  about  1780,  had  analyzed  atmos- 
pheric air  with  remarkable  accuracy,  and  had  even  sep- 
arated the  argon  from  it  and  wondered  what  it  was,  and 
later  Gay-Lussac  had  shown  great  skill  in  the  study  of 
gas  reactions.  During  our  period  gas  analysis  has  been 
further  developed  by  many  chemists.  Bunsen,  in  par- 
ticular, brought  the  art  to  a  high  degree  of  perfection  in 
the  course  of  a  long  period  beginning  about  1838,  the  last 
edition  of  his  *' Methods  of  Gas  Analysis''  having  been 
published  in  1877. 
^  Important  devices  for  the  simplification  of  gas-analy- 
sis in  order  that  it  might  be  used  more  conveniently  for 
technical  purposes  have  been  introduced  by  Orsat  in 
France  and  by  Winkler,  Hempel  and  Bunte  in  Germany. 

It  appears  that  our  countryman  Morley  has  surpassed 
all  others  in  accurate  work  with  gases  in  connection 
with  his  determinations  of  the  combining  weights  and 


298  A  CENTURY  OF  SCIENCE 

volumes  of  hydrogen  and  oxygen  about  the  year  1891. 
Some  of  his  publications  have  appeared  in  the  Journal 
(30,  140,  1885;  41,  220,  1891;  and  others). 

Electrolytic  analysis,  involving  the  deposition  of 
metals,  or  sometimes  of  oxides,  usually  upon  a  platinum 
electrode,  was  brought  into  use  in  1865  by  Wolcott  Gibbs 
through  an  article  published  in  the  Journal  (39,  58, 1865). 
He  there  described  the  electrolytic  precipitation  of  cop- 
per and  of  nickel  by  the  methods  still  in  use.  The  appli- 
cation of  the  process  has  been  extended  to  a  number  of 
other  metals,  and  it  has  been  largely  employed,  particu- 
larly in  technical  analyses.  Important  investigations 
and  excellent  books  on  this  subject  have  been  the  contri- 
butions of  Edgar  F.  Smith  of  the  University  of  Pennsyl- 
vania, and  the  useful  improvement,  the  rotating  cathode, 
was  devised  by  Gooch  and  described  in  the  Journal  (15, 
320,  1903). 

General  Inorganic  Chemistry, 

The  Chemical  Symbols. — It  is  to  Berzelius  that  we  owe 
our  symbols  for  the  atoms,  derived  usually  from  their 
Latin  names,  such  as  C  for  carbon,  Na  for  sodium,  CI  for 
chlorine,  Fe  for  iron,  Ag  for  silver,  and  Au  for  gold. 
"We  owe  to  him  also  the  use  of  small  figures  to  show  the 
number  of  atoms  in  a  formula,  as  in  N2O5.  This  was  a 
marked  improvement  over  the  hieroglyphic  symbols  pro- 
posed by  Dalton,  which  were  set  down  as  many  times  as 
the  atoms  were  supposed  to  occur  in  formulas,  forming 
groups  of  curious  appearance,  but  in  some  respects  not 
unlike  some  of  our  modern  developed  formulas.  The 
advantages  of  Berzelius 's  symbols  were  their  simplicity, 
legibility,  and  the  fact  that  they  could  be  printed  without 
the  need  of  special  type.  It  is  true  that  at  a  later  period 
Berzelius  used  certain  symbols  with  horizontal  lines 
crossing  them  to  represent  double  atoms,  and  that  these 
made  some  difficulty  in  printing.  It  should  be  mentioned 
also  that  Berzelius  at  one  time  made  an  effort  to  simplify 
formulas  by  placing  dots  over  other  symbols  to  represent 
oxygen,  and  commas  to  represent  sulphur  atoms.  Exam- 
ples of  these  are : 

•  •••  >» 

CaS,  calcium  sulphate  ;  Fe,  iron  disulphide 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    299 

This  form  of  notation  was  quite  extensively  employed 
for  a  time,  especially  by  mineralogists,  but  it  was  entirely 
abandoned  later. 

It  is  interesting  to  notice  that  Dalton,  who  lived  until 
1844,  to  reach  the  age  of  78,  differed  from  other  chemists 
in  refusing  to  accept  the  letter-symbols  of  Berzelius. 
In  a  letter  written  to  Graham  in  1837  he  said:  ** Ber- 
zelius's  symbols  are  horrifying.  A  young  student  in 
chemistry  might  as  soon  learn  Hebrew  as  to  make  him- 
self acquainted  with  them.  They  appear  like  a  chaos  of 
atoms  .  .  .  and  to  equally  perplex  the  adepts  of  science, 
to  discourage  the  learner,  as  well  as  to  cloud  the  beauty 
and  simplicity  of  the  atomic  theory. ' ' 

This  forcibly  expressed  opinion  was  apparently  tinged 
with  self-esteem,  but  there  is  no  doubt  that  Dalton  was 
sincere  in  believing  that  the  atoms  were  best  represented 
by  his  circular  symbols,  because,  as  is  well  known,  he 
thought  that  all  the  atoms  were  spherical  in  form,  and  it 
is  evident  that  circles  give  the  proper  picture  of  spherical 
objects.  At  the  present  time  some  insight  as  to  the 
structure  of  atoms  is  being  gained,  and  it  appears  possi- 
ble that  the  time  may  come  when  pictures  of  their 
external  appearance  that  are  not  wholly  imaginary  may 
be  made. 

Changes  in  Formulas. — Even  before  the  year  1826, 
Berzelius  displayed  great  skill  in  arriving  at  many  for- 
mulas that  agree  with  our  present  ones,  for  example,  H2O 
for  water,  ZnClg  for  zinc  chloride,  N2O5  for  nitric  acid 
(anhydride),  CaO  for  calcium  oxide,  CO  and  CO2  for  the 
oxides  of  carbon,  and  many  others.  But  at  the  same 
period  other  authorities,  especially  Gay-Lussac  in  Prance 
and  Gmelin  in  Germany,  on  account  of  a  lack  of  appreci- 
ation for  Avogadro^s  principle  and  for  other  reasons, 
such  as  the  use  of  symbols  to  represent  combining 
weights  rather  than  atoms,  were  using  different  formulas 
for  some  of  these  compounds,  such  as  HO,  ZnCl  and  NO5, 
so  that  their  formulas  for  many  of  the  compounds  of 
hydrogen,  chlorine,  nitrogen  and  several  other  elements 
differed  from  those  of  Berzelius.  The  employment  of 
different  formulas  involved  the  use  of  different  atomic 
or  combining  weights.  For  example,  with  the  formula 
H2O  for  water  the  composition  by  weight  requires  the 


300  A  CENTURY  OF  SCIENCE 

ratio  1  to  16  for  the  weights  of  the  hydrogen  and  oxy- 
gen atoms,  while  with  HO  the  ratio  is  1  to  8. 

Berzelius  attempted  to  bring  about  greater  uniformity 
in  formulas  and  atomic  weights  by  making  changes  in  his 
table  of  atomic  weights  published  in  1826.  He  prac- 
tically doubled  the  relative  atomic  weights  of  hydrogen, 
chlorine,  nitrogen,  and  of  the  other  elements  that  gave 
twice  as  many  atoms  in  his  formulas  as  in  those  of  others, 
and  at  the  same  time  he  wrote  the  symbols  of  these 
elements  with  a  bar  across  them  to  indicate  that  they 
represented  double  atoms.     For  example,  he  wrote : 

HO  Zn€l  NO, 
instead  of 

H,0,  ZnCl.  N,0. 

This  appears  to  have  been  an  unfortunate  concession 
to  the  views  of  others  on  the  part  of  Berzelius,  for  the 
barred  symbols  were  not  generally  adopted,  partly  on 
account  of  difficulties  in  printing,  and  the  great  achieve- 
ment in  theory  made  by  him  was  lost  sight  of  for  a  long 
period  of  time.  , 

The  Law  of  Atomic  Beats. — In  1819,  Dulong  and  Petit 
of  France,  from  experiments  upon  the  specific  heats  of  a 
number  of  solid  elementary  substances,  came  to  the  con- 
clusion that  the  atoms  of  simple  substances  have  equal 
capacities  for  heat,  or  in  other  words,  that  the  specific 
heats  of  elements  multiplied  by  their  atomic  weights  give 
a  constant  called  the  atomic  heat.  For  instance,  the 
specific  heats  of  sulphur,  iron,  and  gold  have  been  given 
as  0-2026,  0-110,  and  0-0324,  while  their  atomic  weights 
are  about  32,  56,  and  197,  respectively;  hence  the  atomic 
heats  obtained  by  multiplication  are  6-483,  6-116,  and 
6-383. 

Further  investigations  showed  that  the  atomic  heats 
display  a  considerable  variation.  Those  of  carbon, 
boron,  beryllium,  and  silicon  are  very  low  at  ordinary 
temperatures,  although  they  increase  and  approach  the 
usual  values  at  higher  temperatures.  More  recent  work 
has  shown,  however,  that  the  specific  heats  of  other  ele- 
ments vary  greatly  with  the  temperature,  almost  disap- 
pearing at  the  temperature  of  liquid  hydrogen,  and  hence 
possibly  disappearing  entirely  at  the  absolute  zero,  where 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    301 

the  electrical  resistance  of  the  metals  appears  to  vanish 
likewise. 

It  has  been  found  that  most  of  the  solid  elements  near 
ordinary  temperatures  give  atomic  heats  that  are 
approximately  64.  Berzelius  applied  the  law  in  fixing 
a  number  of  atomic  weights,  and  its  importance  for  this 
purpose  is  still  recognized. 

It  may  be  mentioned  here  that  two  well-known  Yale 
men,  W.  G.  Mixter  and  E.  S.  Dana,  while  students  in 
Bunsen's  laboratory  at  Heidelberg  in  1873,  made  deter- 
minations of  the  specific  heats  of  boron,  silicon,  and  zir- 
conium. This  was  the  first  determination  of  this  con- 
stant for  zirconium,  and  it  was  consequently  important 
in  establishing  the  atomic  weight  of  that  element. 

Isomorphism  and  Polymorphism. — Mitscherlich  ob- 
served in  1818  that  certain  phosphates  and  arsenates 
have  the  same  crystalline  form,  and  afterwards  he 
reached  the  conclusion  that  identity  in  form  indicates 
similarity  in  composition  in  connection  with  the  number 
of  atoms  and  their  arrangement.  This  law  of  isomorph- 
ism was  of  much  assistance  in  the  establishment  of  cor- 
rect formulas  and  consequently  of  atomic  weights.  For 
instance,  since  the  carbonates  of  barium,  strontium,  and 
lead  crystallize  in  the  same  form,  the  oxides  of  these 
metals  must  have  analogous  formulas.  From  such  con- 
siderations Berzelius  was  able  to  make  several  improve- 
ments in  his  atomic  weight  table  of  1826. 

Mitscherlich  was  the  first  to  observe  two  forms  of 
sulphur  crystals,  and  from  this  and  other  cases  of 
dimorphism  or  of  polymorphism  it  became  evident  that 
analogous  compounds  were  not  necessarily  always  iso- 
morphous,  a  circumstance  which  has  restricted  the 
application  of  the  law  to  some  extent. 

Besides  its  application  in  fixing  analogous  formulas, 
the  law  of  isomorphism  has  come  to  be  of  much  practical 
use  in  the  understanding  and  simplification  of  the  formu- 
las for  minerals,  for  these  natural  crystals  very  often 
contain  several  isomorphous  compounds  in  varying  pro- 
portions, and  an  understanding  of  this  *  isomorphous 
replacement/'  as  it  is  called,  makes  it  possible  to  deduce 
simple  general  formulas  for  them. 

19 


302  A  CENTURY  OF  SCIENCE 

In  some  cases  isomorphism  takes  place  to  a  greater  or 
less  extent  between  substances  which  are  not  chemically- 
similar,  and  this  brings  about  a  variation  in  composition 
which  at  times  has  caused  confusion.  For  instance,  the 
mineral  pyrrhotite  has  a  composition  which  usually 
varies  between  Fe^Sg  and  FcuSia,  and  both  these  formu- 
las have  been  assigned  to  it.  It  was  recently  shown  by 
Allen,  Crenshaw  and  Johnston  in  the  Journal  (33,  169, 
1912)  that  this  is  a  case  where  the  compound  FeS  is 
capable  of  taking  up  various  amounts  of  sulphur 
isomorphously. 

The  idea  of  solid  solution  was  advanced  by  van't  Hoff 
to  explain  the  crystallization  of  mixtures,  including  cases 
of  evident  isomorphism.  This  view  has  been  widely 
accepted,  and  it  has  been  particularly  useful  in  cases 
where  isomorphism  is  not  evident.  Solid  solution 
between  metals  has  been  found  to  be  exceedingly  com- 
mon, many  alloys  being  of  this  character.  A  case  of 
this  kind  was  observed  by  Cooke  and  described  in  the 
Journal  (20,  222,  1855).  He  prepared  two  well-crystal- 
lized compounds  of  zinc  and  antimony  to  which  he  gave 
the  formulas  Zn3Sb  and  ZuoSb,  but  he  observed  that 
excellent  crystals  of  each  could  be  obtained  which  varied 
largely  in  composition  from  these  formulas.  As  the  two 
compounds  were  dissimilar  in  their  formulas  and  crys- 
talline forms,  Cooke  assumed  that  isomorphism  was 
impossible  and  concluded  *^that  it  is  due  to  an  actual 
perturbation  of  the  law  of  definite  proportions,  produced 
by  the  influence  of  mass."  We  should  now  regard  this 
as  a  case  of  solid  solution. 

A  Lack  of  Confidence  in  Avogadro's  Principle. — One 
reason  why  chemists  were  so  slow  in  arriving  at  the 
correct  atomic  weights  and  formulas  was  a  partial  loss 
of  confidence  in  Avogadro's  principle.  About  1826  the 
young  French  chemist  Dumas  devised  an  excellent 
method  for  the  determination  of  vapor  densities  at  high 
temperatures,  and  his  results  and  those  of  others  showed 
some  discrepancies  in  the  expected  densities.  For 
example,  the  vapor  density  of  sulphur  was  found  to  be 
about  three  times  too  great,  that  of  phosphorus  twice  too 
great,  that  of  mercury  vapor  and  that  of  ammonium 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    303 

chloride  only  about  half  large  enough  to  correspond  to 
the  values  expected  from  analogy  and  other  considera- 
tions. Thus,  one  volume  of  oxygen  with  two  volumes  of 
hydrogen  make  two  volumes  of  steam,  but  only  one-third 
of  a  volume  of  sulphur  vapor  was  found  to  unite  with 
two  volumes  of  hydrogen  to  make  two  volumes  of  hydro- 
gen sulphide.  Berzelius  saw  clearly  that  the  results 
pointed  to  the  existence  of  such  molecules  as  Sg,  P4,  and 
Hgi,  but  it  was  not  generally  realized  in  those  days  that 
Avogadro  's  rule  is  fundamentally  reliable,  and  Berzelius 
himself  appears  to  have  lost  confidence  in  it  on  account 
of  these  complications,  for  he  did  not  apply  Avogadro 's 
principle  to  decisions  about  atomic  weights,  except  in  the 
cases  of  substances  gaseous  at  ordinary  temperatures. 

Electro-chemical  Theories.  —  The  observation  was 
made  by  Nicholson  and  Carlisle  in  1800  that  water 
was  decomposed  into  its  constituent  gases  by  the 
electric  current.  Then  in  1803  Berzelius  and  Hisinger 
found  that  salts  were  decomposed  into  their  bases  and 
acids  by  the  same  agency,  and  in  1807  Davy  isolated 
potassium,  sodium,  and  other  metals  afterwards,  by  a 
similar  decomposition.  Since  those  early  times  a  vast 
amount  of  attention  has  been  paid  to  the  relation  of 
electricity  to  chemical  changes,  a  relation  that  is  evi- 
dently of  great  importance  from  the  fact  that  while 
electric  currents  decompose  chemical  compounds,  these 
currents,  on  the  other  hand,  are  produced  by  chemical 
reactions. 

Berzelius  was  particularly  prominent  in  this  direc- 
tion, and  in  1819  he  published  an  elaborate  electro-chem- 
ical theory.  He  believed  that  atoms  were  electrically 
polarized,  and  that  this  was  the  cause  of  their  combina- 
tion with  one  another.  He  extended  this  idea  to  groups 
of  atoms,  particularly  to  oxides,  and  regarded  these 
groups  as  positive  or  negative,  according  to  the  excess  of 
positive  or  negative  electricity  derived  from  their  con- 
stituent atoms  and  remaining  free.  He  thus  arrived  at 
his  dualistic  theory  of  chemical  compounds,  which 
attained  great  prominence  and  prevailed  for  a  long  time 
in  chemical  theory.  According  to  this  idea,  each  com- 
pound was  supposed  to  be  made  up  of  a  positive  and  a 


304  A  CENTURY  OF  SCIENCE 

negative  atom  or  group  of  atoms.  For  example,  the  for- 
mulas for  potassium  nitrate,  calcium  carbonate,  and 
sulphuric  acid  corresponded  to  K0O.N2O5,  CaO.COs  and 
H2O.SO3  where  we  now  write  KNOg,  CaC03  and  H^SO^, 
and  the  theory  was  extended  to  embrace  organic  com- 
pounds also. 

The  eminent  English  chemist  and  physicist  Faraday 
announced  the  important  law  of  electro-chemical  equiva- 
lents in  1834.  This  law  shows  that  the  quantities  of 
elements  set  free  by  the  passage  of  a  given  quantity  of 
electricity  through  their  solutions  correspond  to  the 
chemical  equivalents  of  those  elements.  Faraday  made  a 
table  of  the  equivalents  of  a  number  of  elements,  regard- 
ing them  important  in  connection  with  atomic  weights, 
but  at  that  time  no  sharp  distinction  was  usually  made 
between  equivalents  and  atomic  weights,  and  it  was  not 
fully  realized  that  one  atom  of  a  given  element  may  be 
the  electrical  equivalent  of  several  atoms  of  another. 

Faraday's  law,  which  is  still  regarded  as  fundamen- 
tally exact,  has  been  of  much  practical  use  in  the 
measurement  of  electric  currents  and  in  calculations  con- 
nected with  electro-chemical  processes.  In  discussing 
his  experiments,  Faraday  made  use  of  several  new  terms, 
such  as  **  electrolyte ' '  for  a  substance  which  conducts 
electricity  when  in  solution,  and  is  thus  ^^electrolyzed,'' 
*' electrode,"  ** anode,"  and  *' cathode,"  terms  that  have 
come  into  general  use,  and  finally  *4ons"  for  the  parti- 
cles that  were  supposed  to  '* wander"  towards  the  elec- 
trodes to  be  set  free  there. 

This  term  *4on"  remained  in  comparative  obscurity 
for  more  than  half  a  century,  when  it  was  brought  into 
great  prominence  among  chemists  by  Arrhenius  in  con- 
nection with  the  ionic  theory. 

Cannizzaro^s  Ideas. — Up  to  about  1869  chaos  reigned 
among  the  formulas  used  by  different  chemists.  Various 
compound  radicals  and  numerous  type-formulas  were 
employed,  dualistic  and  unitary  formulas  of  several 
kinds  were  in  use,  but  the  worst  feature  of  the  situation 
was  the  fact  that  more  than  one  system  of  atomic  weights 
was  in  vogue,  so  that  water  might  be  written 

HO,  HO,  or  H,0 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    305 

and  similar  discrepancies  might  appear  in  nearly  all 
formulas  containing  elements  of  different  valencies.  In 
1858,  however,  an  article  by  the  Italian  chemist  Canniz- 
zaro  appeared  in  which  the  outlines  of  a  course  in  chem- 
ical philosophy  were  presented.  This  acquired  wide 
circulation  in  the  form  of  a  pamphlet  at  a  chemical  con- 
vention somewhat  later,  and  it  dealt  so  clearly  and  ably 
with  Avogadro's  principle,  Dulong  and  Petit 's  law,  and 
other  points  in  connection  with  formulas  that  it  led  to  a 
rapid  and  almost  universal  reform  among  those  who 
were  using  unsatisfactory  formulas. 

At  about  this  time  also  the  dualistic  formulas  of  Ber- 
zelius  were  generally  abandoned,  and  hydrogen  came  to 
be  regarded  as  the  characteristic  element  of  all  acids. 
For  instance,  CaO.SOg,  called  ^*  sulphate  of  lime,'^  came 
to  be  written  CaS04  and  was  called  ** calcium  sulphate," 
and  while  it  had  been  shown  as  early  as  1815  by  Davy 
that  *4odic  acid,"  I2O5,  showed  no  acid  reaction  until  it 
was  combined  with  water,  the  accumulation  of  similar 
facts  led  to  the  formulation  of  sulphuric  acid  as  H2SO4 
instead  of  SO3  or  HgO.SO^,  and  that  of  other  **  oxygen 
acids "  in  a  similar  way.  As  a  necessary  consequence  of 
this  view  of  acids,  the  bases  came  to  be  regarded  as  com- 
pounds of  the  **hydroxyl"  group,  OH.  Therefore  the 
formula  for  caustic  soda  came  to  be  written  NaOH 
instead  of  NagO.HgO,  and  so  on. 

The  Periodic  System  of  the  Elements. — The  perio- 
dicity of  the  elements  in  connection  with  their  atomic 
weights  was  roughly  grasped  by  Newlands  in  England, 
who  announced  his  'Haw  of  octaves"  in  1863.  This  was 
at  the  time  when  the  atomic  weights  were  being  modified 
and  their  numerical  relations  properly  shown.  The  sub- 
ject was  worked  out  more  fully  by  L.  Meyer  in  Germany 
a  little  later,  but  it  was  most  clearly  and  elaborately  pre- 
sented by  the  Russian  chemist  Mendeleeff  in  1869. 

In  order  that  this  subject  may  be  explained  to  some 
extent  Mendeleeff 's  table  is  given  here,  with  the  addition 
of  the  recently  discovered  elements  and  some  other  mod- 
ifications. 


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ONE  HUNDRED  YEARS  OF  CHEMISTRY    307 

In  this  table  the  elements  arranged  in  the  order  of 
their  atomic  weights  fall  into  eight  groups  where  the 
known  oxides  progress  regularly,  with  the  exception  of 
two  or  three  elements,  from  R2O  in  Group  I  to  R2O7  in 
Group  VII,  while  in  Group  VIII  two  oxides  (of  ruthen- 
ium and  osmium)  are  known  which  carry  the  progression 
to  RO4. 

It  was  pointed  out  by  Mendeleeff  that,  with  the  excep- 
tion of  series  1  and  2  at  the  top  of  the  table,  the  alternate 
members  of  the  groups  show  particularly  close  relation- 
ships. These  subordinate  groups,  marked  A  and  B,  in 
most  cases  show  remarkable  analogies  and  gradations  in 
their  .properties,  for  example,  in  the  alkali-metals  from 
lithium  to  caesium,  and  in  the  halogens  from  fluorine  to 
iodine.  The  two  divisions  of  a  group  do  not  usually 
show  very  close  relations  to  each  other,  except  in  their 
valency,  and  they  even  display,  in  several  instances, 
opposite  gradations  in  chemical  activity  in  the  order  of 
their  atomic  weights.  For  instance,  caesium  stands  at 
the  electro-positive  end,  while  gold  stands  at  the  electro- 
negative end  of  its  subordinate  group.  The  difference 
between  the  two  divisions  is  very  great  in  Groups  VI  and 
VII,  but  it  is  extreme  in  Group  VIII,  where  heavy  metals 
are  on  one  side  and  inactive  gases  on  the  other.  Many 
authorities  separate  these  gases  into  a  *^ Group  0'^  by 
themselves  at  the  left-hand  side  of  the  table,  but  this  does 
not  change  their  relative  positions,  and  the  plan  may  be 
objected  to  on  the  ground  that  many  vacant  places  are 
thus  left  in  the  groups  VIII  and  0. 

The  periodic  law  has  been  useful  in  rectifying  certain 
atomic  weights.  At  the  outset  Mendeleeff  was  obliged  to 
change  beryllium  from  14-5  (assuming  BcoO^)  to  9 
(assuming  BeO),  and  later  the  atomic  weights  of  indium 
and  uranium  were  changed  to  make  them  fit  the  system. 
All  of  these  changes  have  been  confirmed  by  physical 
means. 

Mendeleeif  found  a  number  of  vacant  places  in  his 
table,^  and  was  thus  able  to  render  further  service  to 
chemical  science  by  predicting  the  properties  of  undis- 
covered elements,  and  his  predictions  were  very  closely 
confirmed  by  the  later  discovery  of  scandium,  gallium, 
and  germanium.     The  table  indicates  that  there  are  still 


308  A  CENTURY  OF  SCIENCE 

two  undiscovered  elements  below  manganese  and  prob- 
ably two  more  among  the  rare-earth  metals.  The  inter- 
esting observation  has  just  recently  been  made  by  Soddy 
that  the  products  of  radioactive  disintegration  appear  to 
pass  in  a  symmetrical  way  through  positions  in  the 
periodic  system,  giving  off  a  helium  molecule  at  alternate 
transformations  until  the  place  of  lead  is  reached.  It 
appears,  therefore,  that  the  five  vacant  places  in  the  table 
above  bismuth  are  probably  occupied  by  these  evanes- 
cent elements,  and  it  is  to  be  noticed  that  all  of  the 
elements  that  have  been  placed  in  this  region  of  high 
atomic  weights  are  radioactive. 

There  are  some  inconsistencies  in  the  periodic  system. 
The  increments  in  the  atomic  weights  are  irregular,  and 
there  are  three  cases,  argon  and  potassium,  cobalt  and 
nickel,  and  tellurium  and  iodine,  where  a  higher  atomic 
weight  is  placed  before  a  lower  one  in  order  to  bring 
these  elements  into  their  undoubtedly  proper  places. 
There  is  a  peculiarity  also  in  the  heavy-metal  division  of 
Group  VIII,  where  three  similar  elements  occur  in  each 
of  three  places,  and  where  the  usual  periodicity  appears 
to  be  suspended,  or  nearly  so,  in  comparison  with  most 
of  the  other  elements.  However,  there  seems  to  be  a 
still  more  remarkable  case  of  this  kind  in  Group  III, 
where  fourteen  metals  of  the  rare-earths  have  been 
placed.  They  are  astonishingly  similar  in  their  chemical 
properties,  hence  it  seems  necessary  to  assume  that 
periodicity  is  suspended  here  throughout  the  wide  range 
of  atomic  weights  from  139  to  174,  where  no  elements 
save  these  have  been  found. 

Several  other  interesting  features  of  the  table  may  be 
pointed  out.  The  chlorides  and  hydrides,  as  indicated 
by  the  **  typical  compounds, '^  show  a  regular  progres- 
sion in  both  directions  towards  Group  IV.  (Where  the 
type-formulas  do  not  apply,  as  far  as  is  known,  to  more 
than  one  or  two  elements,  they  have  been  placed  in 
parentheses  in  the  table  given  here.)  It  is  a  striking 
fact  that  the  acid-forming  elements  occur  together  in  a 
definite  part  of  the  table,  and  that  the  gases  and  other 
non-metallic  elements,  except  the  inactive  gases  of  Group 
VIII,  occur  in  the  same  region. 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    309 

Atomic  Numbers. — As  the  result  of  a  spectroscopic 
study  of  the  wave-lengths  or  frequencies  of  the  X-rays 
produced  when  cathode  rays  strike  upon  anti-cathodes 
composed  of  different  elements,  Moseley  in  1914  discov- 
ered that  whole  numbers  in  a  simple  series  can  be 
attributed  to  the  atoms.  These  atomic  numbers  are:  1 
for  hydrogen,  2  for  helium,  3  for  lithium,  4  for  beryllium, 
and  so  on,  in  the  order  in  which  the  elements  occur  in 
Mendeleeff 's  periodic  table,  and  in  the  cases  of  argon  and 
potassium,  cobalt  and  nickel,  and  tellurium  and  iodine, 
they  follow  the  correct  chemical  order,  while  the  atomic 
weights  do  not.  They  appear  to  indicate,  therefore,  an 
even  more  fundamental  relation  between  the  atoms  than 
that  shown  by  the  atomic  weights. 

These  numbers  are  now  available  for  every  element 
up  to  lead,  and  they  are  particularly  interesting  in  indi- 
cating, on  account  of  missing  numbers,  the  existence  of 
two  undiscovered  elements  in  the  manganese  group,  and 
two  more  among  the  rare-earth  metals,  in  confirmation 
of  the  vacant  places  below  lead  in  Mendeleeff's  table. 

The  Isolation  of  Elements. — In  the  year  1818  about 
53  elements  were  recognized,  and  since  that  time  about 
30  more  have  been  discovered,  but  the  elements  already 
known  comprised  the  more  common  ones,  and  nearly  all 
of  those  which  have  been  commercially  important  A 
few  of  them,  including  beryllium,  aluminium,  silicon, 
magnesium,  and  fluorine,  were  then  known  only  in  their 
compounds,  as  they  had  not  yet  been  isolated  in  the  free 
condition. 

Berzelius  in  1823  prepared  silicon,  a  non-metallic 
element  resembling  carbon  in  many  respects.  This 
element  has  recently  been  prepared  on  a  rather  large 
scale  in  electric  furnaces  at  Niagara  Falls,  and  has  been 
used  for  certain  purposes  in  the  form  of  castings. 

Wohler  created  much  sensation  in  1827  by  isolating 
aluminium  and  finding  it  to  be  a  very  light,  strong  and 
malleable  metal,  stable  in  the  air,  and  of  a  silver-white 
color.  For  a  long  time  this  metal  was  a  comparative 
rarity,  being  prepared  by  the  reduction  of  aluminium 
chloride  with  metallic  sodium;  but  about  25  years^  ago 
Hall,  an  American,  devised  a  method  of  preparing  it  by 


310  A  CENTURY  OF  SCIENCE 

electrolyzing  aluminmm  oxide  dissolved  in  fused  cryo- 
lite. This  process  reduced  the  cost  of  aluminium  to  such 
an  extent  that  it  has  now  come  into  common  use. 

Wohler  and  Bussy  prepared  beryllium  in  1828,  and 
Liebig  and  Bussy  did  the  same  service  for  magnesium  in 
1830.  The  latter  metal  has  come  to  be  of  much  practical 
importance,  both  as  a  very  powerful  reducing  agent  in 
chemical  operations,  and  as  an  ingredient  of  flash-light 
powders  and  of  mixtures  used  for  fireworks.  It  is  also 
used  in  making  certain  light  alloys. 

After  almost  innumerable  attempts  to  isolate  fluorine, 
during  a  period  of  nearly  a  century,  this  was  finally 
accomplished  in  1886  by  Moissan  in  France  by  the  elec- 
trolysis of  anhydrous  hydrogen  fluoride.  The  free 
fluorine  proved  to  be  a  gas  of  extraordinary  chemical 
activity,  decomposing  water  at  once  with  the  formation 
of  hydrogen  fluoride  and  ozonized  oxygen.  This  fact 
explains  the  failure  of  many  previous  attempts  to  pre- 
pare it  in  the  presence  of  water. 

Early  Discoveries  of  New  Elements. — The  remarkable 
activity  of  chemical  research  at  the  beginning  of  our 
period  is  illustrated  by  the  fact  that  three  new  elements 
were  discovered  in  1817.  In  that  year  Berzelius  had  dis- 
covered selenium,  Arfvedson,  working  in  Berzelius 's 
laboratory  had  discovered  the  important  alkali-metal 
lithium,  and  Stromeyer  had  discovered  cadmium. 

In  1826  Ballard  in  France  discovered  bromine  in  the 
mother-liquor  from  the  crystallization  of  common  salt 
from  sea-water.  Bromine  proved  to  be  an  unusually 
interesting  element,  being  the  only  non-metallic  one  that 
is  liquid  at  ordinary  temperatures,  and  being  strikingly 
intermediate  in  its  properties  between  chlorine  and 
iodine.  It  has  been  obtained  in  large  quantities  from 
brines,  and  is  produced  extensively  in  the  United  States. 
The  elementary  substance  and  its  compounds  have  found 
important  applications  in  chemical  operations,  while  the 
bromides  have  been  found  valuable  in  medicine  and 
silver  bromide  is  very  extensively  used  in  photography. 

In  1828  Berzelius  discovered  thorium.  The  oxide  of 
this  metal  has  recently  been  employed  extensively  as  the 
principal  constituent  of  incandescent  gas-mantles,  and 
the  element  has  acquired  particular  importance  from  the 


ONE  HUNDRED  YEARS  OF  CHEMISTRY     311 

fact  that,  like  uranium,  it  is  radio-active,  decomposing 
spontaneously  into  other  elements. 

Vanadium  had  been  encountered  as  early  as  1801  by 
Del  Rio,  who  named  it  *  *  erythronium, ' '  but  a  little  later 
it  was  thought  to  be  identical  with  chromium  and  was  lost 
sight  of  for  a  while.  In  1830,  however,  it  was  re-discov- 
ered by,  and  received  its  present  name  from  Sefstrom  in 
Sweden.  Berzelius  immediately  made  an  extensive 
study  of  vanadium  compounds,  but  he  gave  them  incor- 
rect formulas  and  derived  an  incorrect  atomic  weight  for 
the  element,  because  he  mistook  a  lower  oxide  for  the 
element  itself.  Roscoe  in  England  in  1867  isolated 
vanadium  for  the  first  time,  found  the  right  atomic 
weight,  and  gave  correct  formitlas  to  its  compounds. 
Vanadium  is  particularly  interesting  from  the  fact  that 
it  displays  several  valencies  in  its  compounds,  many  of 
which  are  highly  colored.  It  has  found  important  use  as 
an  ingredient  in  very  small  proportions  in  certain 
** special  steels''  to  which  it  imparts  a  high  degree  of 
resistance  to  rupture  by  repeated  shocks. 

Columbium  was  discovered  early  in  the  nineteenth 
century  in  the  mineral  columbite  from  Connecticut  by 
Hatchett,  an  Englishman,  who  did  not,  however,  obtain 
the  pure  oxide.  It  was  afterwards  obtained  by  Rose  who 
named  it  niobium.  Both  names  for  the  element  are  in 
use,  but  the  former  has  priority.  Attention  was  called 
to  this  fact  by  an  article  in  the  Journal  by  Connell,  an 
Englishman  (18,  392,  1854). 

The  Platinum  Group  of  Metals. — In  1854  a  new  mem- 
ber of  the  platinum  group  of  metals,  ruthenium,  was  dis- 
covered by  Claus.  Platinum  had  been  discovered  about 
the  middle  of  the  eighteenth  century,  while  its  other  rarer 
associates,  iridium,  osmium,  palladium,  and  rhodium,  had 
been  recognized  in  the  very  early  years  of  the  nineteenth 
century.  It  was  during  the  latter  period  that  platinum 
ware  began  to  be  employed  to  a  considerable  extent  in 
chemical  operations,  and  this  use  was  greatly  extended 
as  time  went  on.  The  discovery  was  made  by  Phillips 
in  1831  that  finely  divided  platinum  by  contact  would 
bring  about  the  combination  of  sulphur  dioxide  with 
atmospheric  oxygen,  and  this  application  during  the  past 
20  years  has  become  enormously  important  in  the  sul- 


312  A  CENTURY  OF  SCIENCE 

phuric  acid  industry,  while  other  important  applications 
of  platinum  as  a  **  catalytic  agenf  have  also  been  made. 
Wolcott  Gibbs  and  Carey  Lea  have  contributed  perhaps 
more  than  any  other  recent  chemists  to  a  knowledge  of 
the  platinum  metals.  Carey  Lea  (38,  81,  248,  1864) 
dealt  chiefly  with  the  separation  of  the  metals  from  each 
other,  while  Gibbs 's  work  (31,  63,  1861;  34,  341,  1862) 
included  investigations  of  many  of  the  compounds. 
^  It  may  be  mentioned  that  while  platinum  and  its  asso- 
ciates were  formerly  known  only  in  the  uncombined  con- 
dition in  nature,  the  arsenide  sperrylite,  PtAss,  was 
described  by  the  late  S.  L.  Penfield,  and  the  senior  writer 
of  this  chapter,  in  articles  published  in  the  Journal  (37, 
67,  71,  1889). 

Applications  of  the  Spectroscope. — The  discovery  in 
certain  mineral  waters  of  the  rare  alkali-metals  rubidium 
and  caesium  by  Bunsen  and  Kirchoif  in  1861  was  in  conse- 
quence of  the  application  of  spectroscopy  by  these  same 
scientists  a  short  time  previously  to  the  identification  of 
elements  imparting  colors  to  the  flame.  Since  that  time 
the  employment  of  the  spectroscope  for  chemical  pur- 
poses has  been  much  extended,  as  it  has  been  used  in  the 
examination  of  light  from  electric  sparks  and  arcs,  as 
well  as  from  Geissler  tube  discharges  and  from  colored 
solutions. 

The  metals  rubidium  and  caesium  are  interesting  in 
being  closely  analogous  to  potassium  and  in  standing  at 
the  extreme  electro-positive  end  of  the  series  of  known 
metals.  It  should  be  noticed  here  that  Johnson  and 
Allen  of  our  Sheffield  Laboratory,  having  obtained  a 
good  supply  of  rubidium  and  caesium  material  from  the 
lepidolite  of  Hebron,  Maine,  made  some  important 
researches  upon  these  elements,  accounts  of  which  were 
published  in  the  Journal  (34,  367,  1862;  35,  94,  1863). 
They  established  the  atomic  weight  of  caesium,  thus  cor- 
recting Bunsen  *s  determination  which  was  unsatisfac- 
tory on  account  of  the  small  quantity  and  impurity  of  his 
material.  Pollucite,  a  mineral  rich  in  caesium,  which  had 
been  found  in  very  small  amount  on  the  Island  of  Elba, 
has  more  recently  been  obtained  in  large  quantities—hun- 
dreds of  pounds — at  Paris,  Maine,  and  its  vicinity. 
This  American  pollucite  was  first  analyzed  and  identi- 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    313 

fied  by  the  senior  writer  of  this  article  (41,  213,  1891), 
and  later  (43,  17,  1892  et  seq.)  the  results  of  many  inves- 
tigations on  cassium  and  rubidium  compounds,  in  which 
the  junior  writer  played  an  important  part,  carried  out 
in  Sheffield  Laboratory,  were  published  in  the  Journal. 

The  application  of  the  spectroscope  led  to  the  discov- 
ery of  thallium  in  1861  by  Crookes  of  England,  and  to 
that  of  indium  in  1863  by  Reich  and  Richter  in  Germany. 
Both  of  these  metals  are  extremely  rare,  but  they  are  of 
considerable  theoretical  interest.  Thallium  is  particu- 
larly remarkable  in  showing  resemblances  in  its  different 
compounds  to  several  groups  of  metals. 

The  spectroscope  was  employed  again  in  connection 
with  the  discovery  of  gallium  in  1875  by  Boisbaudran. 
It  is  in  the  same  periodic  group  as  thallium  and  indium, 
and  it  has  a  remarkably  low  melting  point,  just  above 
ordinary  room-temperature.  It  has  been  among  the 
rarest  of  the  rare  elements,  but  within  two  or  three  years 
a  source  of  it  has  been  found  in  the  United  States  in  cer- 
tain residues  from  the  refining  of  commercial  zinc.  The 
recent  issues  of  the  Journal  (41,  351, 1916;  42,  389, 1916) 
show  that  Browning  and  Uhler  of  Yale  have  availed 
themselves  of  this  new  material  in  order  to  make  import- 
ant chemical  and  physical  researches  upon  this  metal. 

Germanium. — The  discovery  of  germanium  in  the  min- 
eral argyrodite  in  1886  by  Winkler  revealed  a  curious 
metal  which  gives  a  white  sulphide  that  may  be  easily 
mistaken  for  sulphur  and  which  is  volatilized  completely 
when  its  hydrochloric  acid  solution  is  evaporated,  so  that 
it  is  evasive  in  analytical  operations.  This  element  had 
been  predicted  with  much  accuracy  by  Mendeleeff,  and 
it  is  rather  closely  related  to  tin. 

A  few  years  after  the  discovery  of  germanium.  Pen- 
field  published  in  the  Journal  (46,  107,  1893;  47,  451, 
1894)  some  analyses  of  argyrodite,  correcting  the  for- 
mula given  by  Winkler  to  the  mineral ;  also  he  described 
canfieldite,  an  analogous  mineral  from  Bolivia,  in  which 
a  large  part  of  the  germanium  was  replaced  by  tin. 

The  Rare  Earths. — Before  the  year  1818  two  rare 
earths,  the  oxides  of  yttrium  and  cerium,  were  known 
in  an  impure  condition.  Since  that  time  about  fourteen 
others  have  been  discovered  as  associates  of  the  first 


314  A  CENTURY  OF  SCIENCE 

two.  The  rare  earths  are  peculiar  from  the  fact  that 
many  of  them  are  always  found  mixed  together  in  the 
minerals  containing  them,  and  also  from  the  circum- 
stance that  most  of  them  are  remarkably  similar  in  their 
chemical  reactions  and  consequently  exceedingly  difficult 
to  separate  from  each  other.  In  many  cases  multitudes 
of  fractional  precipitations  or  crystallizations  are  needed 
to  obtain  pure  salts  of  a  number  of  these  metals.  The 
solutions  of  the  salts  of  several  of  these  elements  give 
characteristic  absorption  bands  when  examined  spectro- 
scopically  by  the  use  of  transmitted  light. 

No  important  practical  application  has  been  found  for 
any  of  these  earthy  oxides,  except  that  about  one  per  cent 
of  cerium  oxide  is  mixed  with  thorium  oxide  in  incandes- 
cent gas-mantles  in  order  to  obtain  greatly  increased 
luminosity. 

The  Inactive  Gases. — As  long  ago  as  1785,  Cavendish, 
that  remarkable  Englishman  who  first  weighed  the  world 
and  first  discovered  the  composition  of  water,  actually 
obtained  a  little  argon  in  a  pure  condition  by  sparking 
atmospheric  nitrogen  with  oxygen  converting  it  into 
nitric  acid  (another  discovery  of  his)  and  absorbing  the 
excess  of  oxygen.  The  volume  of  this  residual  gas  as 
estimated  by  him  corresponds  very  closely  to  the  volume 
of  argon  in  the  atmosphere,  as  now  known. 

It  was  more  than  a  century  later,  in  1894,  that  Rayleigh 
and  Ramsay  discovered  argon  in  the  air.  Lord  Rayleigh 
had  found  that  atmospheric  nitrogen  was  about  one-half 
per  cent  heavier  than  chemical  nitrogen,  a  fact  which  led 
to  the  investigation.  It  was  only  necessary  to  repeat 
Cavendish's  experiment  on  a  large  scale,  or  to  absorb 
oxygen  with  hot  copper  and  nitrogen  with  hot  mag- 
nesium, in  order  to  obtain  argon.  The  gas  attracted 
much  attention,  both  on  account  of  having  but  a  single 
atom  in  its  molecule,  and  particularly  because  it  failed  to 
enter  into  chemical  combination  of  any  kind.  This  gas 
has  been  used  of  late  for  filling  the  bulbs  of  incandescent 
electric  lamps  in  cases  where  a  gas-pressure  without 
chemical  action  is  desired. 

In  1890  and  1891,  Hillebrand  published  in  the  Journal 
40,  384,  1890:  42,  390,  1891)  a  series  of  analyses  of  the 
mineral  uraninite  and  reported  in  some  samples  of  the 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    315 

mineral  as  much  as  2-5  per  cent  of  an  inactive  gas. 
Hillebrand  examined  the  gas  spectroscopically  but,  just 
missing  an  important  discovery,  he  detected  only  the 
spectrum  lines  of  nitrogen.  Ramsay,  in  searching  for 
argon  in  some  sort  of  natural  combination,  and  doubt- 
less remembering  Hillebrand 's  work,  heated  some 
cleveite,  a  variety  of  uraninite,  and  obtained,  not  argon, 
but  a  new  gas.  This  gave  a  yellow  spectrum-line  cor- 
responding to  a  line  previously  observed  in  the  light  of 
the  sun's  corona  and  attributed  to  an  element  in  the  sun 
called  helium.  Helium,  therefore,  in  1895  had  been  found 
on  the  earth.  This  gas  is  a  constant  constituent  of 
uranium  minerals,  as  it  is  produced  by  the  breaking  down 
of  radioactive  elements.  It  has  been  found  in  very  small 
quantity  in  the  atmosphere,  and  is  the  most  difficult  of  all 
known  gases  to  liquefy,  as  its  boiling  point,  as  shown  by 
Onnes  in  1908,  is  only  4°  above  the  absolute  zero.  It  has 
not  yet  been  solidified. 

In  1898  Ramsay  and  Travers,  by  the  use  of  ingenious 
methods  of  fractional  distillation  and  absorption  by  char- 
coal, obtained  three  other  much  rarer  inactive  gases 
from  the  atmosphere  which  they  called  neon,  krypton  and 
xenon. 

The  inactive  gases  are  all  colorless,  and  as  they  form 
no  chemical  compounds  they  are  characterized  by  their 
densities,  which  give  their  atomic  weights,  by  their  boil- 
ing points,  and  by  their  characteristic  Geissler-tube  spec- 
tra. 

The  gaseous  radium  emanation,  or  niton,  belongs  also 
to  the  inactive  group,  and  it  was  also  collected  and 
studied  by  Ramsay  who  was  compelled  to  work  with  only 
0-0001  cc.  of  it,  as  the  volume  obtained  by  heating  radium 
salts  is  very  small.  It  is  an  evanescent  element,  disap- 
pearing within  a  few  days  on  account  of  radioactive  dis- 
integration. Meanwhile  it  glows  brilliantly  when  lique- 
fied and  cooled  to  the  temperature  of  liquid  air.  It  has 
an  atomic  weight  of  222,  four  units  below  that  of  radium, 
and  the  difference  is  considered  as  due  to  the  loss  by 
radium  of  an  atom  of  helium  in  passing  into  the 
emanation. 

The  Radioactive  Elements. — The  discovery  of  radium 
in  1898  by  Madame  Curie,  and  the  study  of  that  and  other 


316  A  CENTURY  OF  SCIENCE 

radioactive  elements  has  produced  a  profound  effect 
upon  chemical  theory.  It  was  found  that  the  two  ele- 
ments of  the  highest  atomic  weights,  uranium  and 
thorium,  are  always  spontaneously  decomposing  into 
other  elements  at  a  fixed  rate  of  speed  which  can  be  con- 
trolled by  no  artificial  means,  and  that  the  elements 
resulting  from  these  decompositions  likewise  undergo 
spontaneous  changes  into  still  other  elements  at  greatly 
varying  rates  of  speed,  forming  in  each  case  a  remark- 
able series  of  temporary  elements.  These  transforma- 
tions are  accompanied  by  the  emission  at  enormous 
velocities  of  three  kinds  of  rays,  one  variety  of  which  has 
been  sho^vn  to  consist  of  helium  atoms.  The  greater 
number  of  the  elements  formed  in  these  transformations 
have  not  as  yet  been  obtained  in  a  pure  condition,  and 
they  are  known  only  in  connection  with  their  radio- 
activity, volatility,  etc.;  but  radium  and  niton,  two  of 
these  products,  have  been  obtained  in  a  pure  condition, 
so  that  their  atomic  weights  and  their  places  in  the 
periodic  system  have  been  fixed. 

We  owe  much  of  our  knowledge  of  the  radioactive 
transformations  to  the  researches  of  Rutherford  and  of 
Soddy,  and  of  their  co-workers,  but  one  of  the  important 
products  of  the  transformation  of  uranium,  an  element 
which  he  called  ionium,  was  characterized  by  Boltwood  of 
Yale  (25,  365,  1908). 

Radium  and  niton,  apart  from  their  radioactive  prop- 
erties, resemble  barium  and  the  inert  gases  of  the  atmos- 
phere, respectively.  The  rates  at  which  their  progeni- 
tors produce  them,  and  the  rates  at  which  they  themselves 
decompose,  bring  about  a  state  of  equilibrium  after  a 
time.  Therefore  a  given  amount  of  uranium,  which 
decomposes  exceedingly  slowly,  can  yield  even  after 
thousands  of  years  only  a  very  small  proportional 
quantity  of  undecomposed  radium,  one-half  of  which 
disappears  in  about  2500  years,  because  the  amount 
decomposed  must  eventually  be  equal  to  the  amount  pro- 
duced. The  first  conclusive  evidence  that  radium  is  a 
product  of  the  decomposition  of  uranium  was  given  by 
Boltwood  in  the  Journal  (18,  97,  1904).  He  found  that 
all  uranium  minerals  contain  radium;  and  the  amount 
of  radium  present  is  always  proportional  to  the  amount 


ONE  HUNDRED  YEARS  OF  CHEMISTRY  317 

of  uranium,  which  shows  the  genetic  relation  between 
the  two. 

In  the  case  of  niton,  which  is  produced  by  radium,  and 
is  called  also  the  radium  emanation,  the  rate  of  decay  is 
rapid,  so  that  if  the  gas  is  expelled  from  radium  by  heat- 
ing, equilibrium  is  reached  after  a  few  days,  with  the 
accumulation  of  the  largest  possible  amount  of  niton. 

The  conclusion  has  been  reached  by  Rutherford  and 
others  that  the  final  product  besides  helium,  in  the  radio- 
active transformations,  is  lead,  or  at  least  an  element 
or  elements  resembling  lead  to  such  a  degree  that  no 
separation  of  them  by  chemical  means  is  possible. 
Atomic  weight  determinations  by  Richards  and  others 
have  shown  that  specimens  of  lead  found  in  radioactive 
minerals  give  distinctly  different  atomic  weights  from 
that  of  ordinary  lead.  This  fact  has  led  to  the  view  that 
possibly  the  atoms  of  the  elements  are  not  all  of  the  same 
weight,  but  vary  within  certain  limits — a  view  that  is 
contrary  to  previous  conclusions  derived  from  the  uni- 
formity in  atomic  weights  obtained  with  material  from 
many  different  sources. 

The  results  of  the  investigations  upon  radioactivity 
have  led  to  modified  views  in  regard  to  the  stability  of 
the  elements  in  general.  There  has  been  little  or  no 
proof  obtained  that  any  artificial  transmutation  of  the 
elements  is  possible,  but  the  spontaneous  transformation 
of  the  radioactive  elements  brings  forward  the  possibility 
that  other  elements  are  changing  imperceptibly,  and  that 
a  state  of  evolution  exists  among  them.  All  of  the  radio- 
active changes  that  we  know  proceed  from  higher  to 
lower  atomic  weights,  and  we  are  entirely  ignorant  of  the 
process  by  which  uranium  and  thorium  must  have  been 
produced  originally. 

Since  radioactive  changes  have  been  found  to  be 
accompanied  by  the  release  of  vast  amounts  of  energy, 
compared  with  which  the  energy  of  chemical  reactions  is 
trivial,  a  new  aspect  in  regard  to  the  structure  of  atoms 
has  arisen, — they  must  be  complex  in  structure,  the  seats 
of  enormous  energy. 

The  determination  of  the  amount  of  radium  in  the 
earth 's  crust  has  indicated  that  the  heat  produced  by  it  is 
amply  sufficient  to  supply  the  loss  of  heat  due  to  radia- 

20 


318  A  CENTUEY  OF  SCIENCE 

tion,  and  this  source  of  heat  is  regarded  by  many  as  the 
cause  of  volcanic  action.  The  sun's  radiant  heat  also 
has  been  supposed  to  be  supplied  by  radioactive  action, 
so  that  the  older  views  regarding  the  limitation  of  the 
age  of  the  earth  and  the  solar  system  on  account  of  loss  of 
heat  have  been  considerably  modified  by  our  knowledge 
of  radioactivity. 

Physical  Chemistry, 

The  application  of  physical  methods  as  aids  to  chem- 
ical science  began  in  early  times,  and  some  of  these,  such 
as  the  determinations  of  gas  and  vapor  densities,  specific 
heats,  and  crystalline  forms  have  been  mentioned  already 
in  this  article.  Within  recent  times  physical  chemistry 
has  greatly  developed  and  a  few  of  its  important  achieve- 
ments will  now  be  described. 

Molecular  Weight  Determinations. — Gas  and  vapor 
densities  in  connection  with  Avogadro's  principle, 
formed  the  only  basis  for  molecular  weight  determina- 
tions until  comparatively  recent  times.  The  early 
methods  of  Gay-Lussac  and  Dumas  for  vapor  density 
were  supplemented  in  1868  by  the  method  of  Hofmann, 
whereby  vapors  were  measured  under  diminished  pres- 
sure over  mercury.  In  1878  Victor  Meyer  introduced  a 
simpler  method  depending  upon  the  displacement  of  air 
or  other  gas  by  the  vapor  in  a  heated  tube.  As  refrac- 
tory tubes,  such  as  those  of  porcelain  or  even  iridium, 
could  be  used  in  this  method,  molecular  weights  at 
extremely  high  temperatures  were  determined  with  inter- 
esting results.  For  instance,  it  was  found  that  iodine 
vapor,  which  shows  the  molecule  Ig  at  lower  tempera- 
tures, gradually  becomes  monatomic  with  rise  in  tem- 
perature, that  sulphur  vapor  dissociates  from  Sg  to  Sg 
under  similar  conditions,  and  that  most  of  the  metals, 
including  silver,  have  monatomic  vapors. 

In  1883  and  later  it  was  pointed  out  by  Raoult  that  the 
molecular  weights  of  substances  could  be  found  from  the 
freezing  points  of  their  solutions,  but  this  method  was 
complicated  from  the  fact  that  salts,  strong  acids  and 
strong  bases  behaved  quite  differently  from  other  sub- 
stances in  this  respect,  and  allowances  had  to  be  made  for 
the  types  of  substances  used.     The  complication  was 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    319 

afterwards  explained  by  the  ionization  theory  of  Arr- 
henius.  Better  apparatus  for  this  method  was  soon 
devised  by  Beckmann,  who  introduced  also  a  method 
depending  upon  the  boiling  points  of  solutions,  and  these 
two  methods  are  still  the  standard  ones  for  determining 
molecular  weights  in  solution.  They  are  very  exten- 
sively employed  by  organic  chemists. 

It  has  been  found  that  the  majority  of  substances  when 
dissolved  have  the  same  molecular  weight  as  in  the 
gaseous  condition,  provided  that  they  can  be  volatilized 
at  comparable  temperatures.  For  instance,  sulphur  in 
solution  has  the  formula  Sg,  iodine  is  I2  and  the  metals 
are  monatomic. 

VanH  Hoff's  Law  and  Arrhenius's  Theory  of  Ions, — 
Modern  views  on  solutions  date  largely  from  1886,. when 
van't  Hoff  called  attention  to  the  relations  existing 
between  the  osmotic  pressure  exerted  by  dissolved  sub- 
stances and  gas  pressure. 

Pfeffer,  a  botanist,  was  the  first  to  measure  osmotic 
pressure  (1877).  Basing  his  conclusions  chiefly  upon 
Pfeffer's  determinations,  van't  Hoff  formulated  a  new 
and  highly  important  law,  which  may  be  stated  as  fol- 
lows :  The  osmotic  pressure  exerted  by  a  substance  in 
solution  is  equal  to  the  gas  pressure  that  the  substance 
would  exert  if  it  were  a  gas  at  the  same  temperature  and 
the  same  volume.  Further  investigations  have  fully 
established  the  fact  that  molecules  in  dilute  solution  obey 
the  simple  laws  of  gases. 

It  was  pointed  out  by  van't  Hoff  that  salts,  strong 
acids  and  strong  bases  showed  marked  exceptions  to  his 
law  in  exerting  much  greater  osmotic  pressures  than 
those  calculated  for  them. 

The  next  year  in  1887,  Arrhenius  explained  this  abnor- 
mal behavior  of  salts,  strong  acids  and  strong  bases  by 
assuming  that  they  dissociate  spontaneously  into  ions 
Avhen  they  dissolve,  and  that  these  more  numerous  par- 
ticles act  like  molecules  in  producing  osmotic  pressure. 
He  showed^  that  these  exceptional  substances  all  conduct 
electricity  in  solution,  while  those  conforming  with  van't 
Hoif 's  law  do  not,  and  according  to  his  theory  the  ions 
become  positively  or  negatively  charged  when  they  are 
formed,  and  these  charged  ions  conduct  the   current. 


320  A  CENTURY  OF  SCIENCE 

For  example  a  molecule  of  sodium  chloride  was  supposed 
to  give  the  two  ions  Na+  and  CI",  thus  exerting  twice  as 
much  osmotic  pressure  as  a  single  molecule. 

Determinations  of  osmotic  pressure  or  related  values, 
such  as  depression  of  the  freezing  point  and  of  electric 
conductivity,  indicated  that  ionization  could  not  be 
regarded  as  complete  in  any  case  except  in  exceedingly 
dilute  solutions,  and  that  the  extent  of  ionization  varied 
with  different  substances.  The  fact  that  osmotic  pres- 
sures and  electric  conductivities  gave  closely  agreeing 
results  in  regard  to  the  extent  of  ionization  in  various 
cases,  is  the  strongest  evidence  in  support  of  the  theory. 

It  was  difficult  at  first  for  many  chemists  to  believe 
that  atoms,  such  as  those  of  sodium  and  chlorine,  and 
groups  such  as  NH4  and  SO4  could  exist  independently 
in  solution,  even  though  electrically  charged.  However, 
the  theory  rapidly  gained  ground  and  is  now  accepted 
by  nearly  every  chemist  as  a  satisfactory  explanation  of 
many  facts. 

During  recent  years,  many  investigations  relating  to 
osmotic  pressure  and  ionization  have  been  carried  out  in 
the  United  States,  but  only  the  work  of  Morse,  A.  A. 
Noyes,  and  the  late  H.  C.  Jones  can  be  merely  alluded  to 
here.  It  should  be  mentioned  that  the  eminent  author 
of  the  ionic  hypothesis  gave  the  Silliman  Memorial  course 
of  lectures  at  Yale  in  1911  on  Theories  of  Solution. 

Colloidal  Solutions. — Graham,  an  English  chemist,  in 
1861  was  the  first  to  make  a  distinction  between  sub- 
stances forming  true  solutions,  which  he  called  crystal- 
loids, and  those  of  a  gummy  nature  resembling  glue, 
which  in  solution  do  not  diffuse  readily  through  parch- 
ment membranes,  as  crystalloids  do,  and  which  he  called 
colloids.  The  separation  of  colloids  by  means  of  parch- 
ment was  called  dialysis,  and  this  process  has  come  into 
extensive  use  in  preparing  pure  colloidal  solutions. 
Slow  diffusion  is  now  regarded  as  characteristic  of  col- 
loids rather  than  their  gummy  condition. 

Colloidal  solutions  occupy  an  intermediate  position 
between  true  solutions  and  suspensions,  resembling  one 
or  the  other  according  to  the  kind  of  colloi(J  and  the  fine- 
ness of  division.  By  preparing  filters  with  pores  of 
varying  degrees  of  fineness,  Bechold  has  been  able  to 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    321 

separate  colloids  from  each  other  in  accordance  with  the 
size  of  their  particles.  It  has  also  been  possible  to  pre- 
pare different  solutions  of  a  colloid  varying  gradually 
from  one  in  which  the  particles  were  undoubtedly  in  sus- 
pension to  one  which  had  many  of  the  properties  of  a 
true  solution. 

Beginning  in  1889,  Carey  Lea  described  iii  the  Journal 
37,  476,  1889  et  seq.)  a  variety  of  methods  for  preparing 
colloidal  solutions  of  the  metals,  consisting  in  general  of 
treating  solutions  of  metallic  salts  with  mild  reducing 
agents.  His  work  on  colloidal  silver  was  particularly 
extensive  and  interesting.  Solutions  of  this  kind  have 
recently  yielded  some  extremely  interesting  results  by 
means  of  the  ultra-microscope,  an  apparatus  devised  by 
Zsigmondy  and  Siedentopf.  A  very  intense  beam  of 
light  is  passed  through  the  solution  and  observed  at  right 
angles  with  a  powerful  microscope.  Under  these  condi- 
tions, particles  much  too  small  to  be  seen  by  other  means, 
reveal  their  presence  by  reflected  light.  It  has  been  pos- 
sible in  a  very  dilute  solution  of  known  strength  to  count 
the  particles  and  thus  to  calculate  their  size.  The  small- 
est colloidal  particles  measured  in  this  way  were  of  gold 
and  were  shown  to  have  approximately  ten  times  the 
diameter,  or  1000  times  the  volume,  attributed  to  ordi- 
nary molecules.  It  is  of  interest  that  the  particles 
appear  in  rapid  motion  corresponding  to  the  well-known 
Brownian  movement. 

The  chemistry  of  colloids  has  now  assumed  such 
importance  that  it  may.  be  considered  as  a  separate 
branch  of  the  science.  It  has  its  own  technical  journal 
and  deals  largely  with  the  chemistry  of  organic  products. 
All  living  matter  is  built  up  of  colloids,  and  haemoglobin, 
starch,  proteins,  rubber  and  milk  are  examples  of  col- 
loidal substances  or  solutions.  Among  inorganic  sub- 
stances, many  sulphides,  silicic  acid,  and  the  amorphous 
hydroxides,  like  ferric  hydroxide,  frequently  act  as 
colloids. 

Law  of  Mass-Action, — ^Berthollet  about  the  beginning 
of  the  last  century  was  the  first  chemist  to  study  the 
effect  of  mass,  or  more  correctly,  the  concentration  of 
substances  on  chemical  action.  His  views  summarized 
by  himself  are  as  follows :    *  *  The  chemical  activity  of  a 


322  A  CENTURY  OF  SCIENCE 

substance  depends  upon  the  force  of  its  affinity  and  upon 
the  mass  which  is  present  in  a  given  volume.'*  The 
development  of  this  idea,  which  is  fundamentally  correct, 
was  greatly  hindered  by  the  fact  that  Berthollet  drew  the 
incorrect  conclusion  that  the  composition  of  chemical 
compounds  depended  upon  the  masses  of  the  substances 
combining  to  produce  them,  a  conclusion  in  direct  con- 
tradiction to  the  law  of  definite  proportions,  and  since 
this  view  was  soon  disproved  by  Proust  and  others, 
Berthollet 's  law  in  its  other  applications  received  no 
immediate  attention.  Mitchell,  however,  pointed  out 
in  the  Journal  (16,  234,  1829)  the  importance  of 
Berthollet 's  work,  and  Heinrich  Rose  in  1842  again 
called  attention  to  the  effect  of  mass,  mentioning  as  one 
illustration  the  effect  of  water  and  carbonic  acid  in 
decomposing  the  very  stable  natural  silicates.  Some- 
what later  several  other  chemists  made  important  contri- 
butions to  the  question  of  the  influence  of  concentration 
upon  chemical  action,  but  it  was  the  Norwegians,  Guld- 
berg  and  Waage,  who  first  formulated  the  law  of  mass 
action  in  1867. 

This  law  has  been  of  enormous  importance  in  chemical 
theory,  since  it  explains  a  great  many  facts  upon  a 
mathematical  basis.  It  applies  particularly  to  equilib- 
rium in  reversible  reactions,  where  it  states  that  the 
product  of  the  concentrations  on  the  one  side  of  a  simple 
reversible  equation  bears  a  constant  relation  to  the 
products  of  the  concentrations  on  the  other  side,  provided 
that  the  temperature  remains  constant.  In  cases  of  this 
kind  where  two  gases  or  vapors  react  with  two  solids, 
the  latter  if  always  in  excess  may  be  regarded  as  con- 
stant in  concentration,  and  the  law  takes  on  a  simpler 
aspect  in  applying  only  to  the  concentrations  of  the 
gaseous  substances.  For  example,  in  the  reversible 
reaction 

3Fe  +  4Hp:;=±Fe,0,  +  4H„ 

which  takes  place  at  rather  high  temperatures,  a  definite 
mixture  of  steam  and  hydrogen  at  a  definite  temperature 
will  cause  the  reaction  to  proceed  with  equal  rapidity  in 
both  directions,  thus  maintaining  a  state  of  equilibrium, 
provided  that  both  iron  and  the  oxide  are  present  in 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    323 

excess.  If,  however,  the  relative  concentrations  of  the 
hydrogen  and  steam  are  changed,  or  even  if  the  tempera- 
ture is  changed,  the  reaction  will  proceed  faster  in  one 
direction  than  in  the  other  until  equilibrium  is  again 
attained. 

The  principle  of  mass-action  also  explains  why  it  is 
sometimes  possible  for  a  reversible  reaction  to  become 
complete  in  either  direction.  For  instance,  in  connec- 
tion with  the  reaction  that  has  just  been  considered,  if 
steam  is  passed  over  heated  iron  and  if  hydrogen  is 
passed  over  the  heated  oxide,  the  gaseous  product  in  each 
case  is  gradually  carried  away,  and  the  reaction  contin- 
ually proceeds  faster  in  one  direction  than  in  the  other 
until  it  is  complete,  according  to  the  equations 

3Fe  +  4H,0 >  SFefi^  +  4X1,     and 

Fe,0,  +  4H, >  3Fe  +  4H,0. 

Many  other  well-known  and  important  facts,  both 
chemical  and  physical,  depend  upon  this  law.  It  explains 
the  circumstance  that  a  vapor-pressure  is  not  dependent 
upon  the  amount  of  the  liquid  that  is  present;  it  also 
explains  the  constant  dissociation  pressure  of  calcium 
carbonate  at  a  given  temperature,  irrespective  of  the 
amounts  of  carbonate  and  oxide  present;  in  connection 
with  the  ionic  theory,  it  furnishes  the  reason  for  the 
variable  solubility  of  salts  due  to  the  presence  of  elec- 
trolytes containing  ions  in  common;  and  it  elucidates 
Henry's  law  which  states  that  the  solubilities  of  gases  are 
proportional  to  their  pressures. 

Ostwald,  more  than  any  other  chemist,  has  been  instru- 
mental in  making  general  applications  of  this  law,  and  he 
made  particularly  extensive  use  of  it  in  connection  with 
analytical  chemistry  in  a  book  upon  this  subject  which  he 
published. 

The  Phase  Rule.— In  1876  Willard  Gibbs  of  Yale  pub- 
lished a  paper  in  the  Proceedings  of  the  Connecticut 
Academy  of  Science  on  the  **  Equilibrium  of  Heteroge- 
neous Substances,''  and  two  years  later  he  published  an 
abstract  of  the  article  in  the  Journal  (16,  441, 1878).  He 
had  discovered  a  new  law  of  nature  of  momentous 
importance   and  wide  application  which  is  called  the 


324  A  CENTURY  OF  SCIENCE 

**  Phase-Rule ' '  and  is  expressed  by  a  very  simple 
formula. 

The  application  of  this  great  discovery  to  chemical 
theory  was  delayed  for  ten  years,  partly,  perhaps, 
because  it  was  not  sufficiently  brought  to  the  attention  of 
chemists,  but  largely  it  appears  because  it  was  not  at 
first  understood,  since  its  presentation  was  entirely 
mathematical. 

It  was  Rooseboom,  a  Dutch  chemist,  who  first  applied 
the  phase-rule.  It  soon  attracted  profound  attention, 
and  the  name  of  Willard  Gibbs  attained  world-wide  fame 
among  chemists.  When  Nernst,  who  is  perhaps  the  most 
eminent  physical  chemist  of  the  present  time,  was  deliv- 
ering the  Silliman  Memorial  Lectures  at  Yale  a  few  years 
ago,  he  took  occasion  to  place  a  wreath  on  the  grave  of 
Willard  Gibbs  in  recognition  of  his  achievements. 

To  understand  the  rule,  it  is  necessary  to  define  the 
three  terms,  introduced  by  Gibbs,  phase,  degrees  of  free- 
dom and  component. 

By  the  first  term,  is  meant  the  parts  of  any  system  of 
substances  which  are  mechanically  separable.  For 
instance,  water  in  contact  with  its  vapor  has  two  phases, 
while  a  solution  of  salt  and  water  is  composed  of  but  one. 
The  degrees  of  freedom  are  the  number  of  physical  con- 
ditions, including  pressure,  temperature  and  concentra- 
tion, which  can  be  varied  independently  in  a  system 
without  destroying  a  phase.  The  exact  definition  of  a 
component  is  not  so  simple,  but  in  general,  the  com- 
ponents of  a  system  are  the  integral  parts  of  which  it  is 
composed.  Any  system  made  up  of  the  compound  HgO, 
for  instance,  whether  as  ice,  water  or  vapor,  contains  but 
one  component,  while  a  solution  of  salt  and  water  con- 
tains two.  Letting  P,  F.  and  C  stand  for  the  three  terms, 
the  phase-rule  is  simply 

F  =  C-f2  — P 

that  is,  the  number  of  degrees  of  freedom  in  a  system  in 
equilibrium  equals  the  number  of  components,  plus  two, 
minus  the  number  of  phases.  The  rule  can  be  easily 
understood  by  means  of  a  simple  illustration.  In  a  sys- 
tem composed  of  ice,  water  and  water-vapor,  there  are 
three  phases  and  one  component  and  therefore 


Jc,    /t^^iZ^^:4.^^i.^c^  yS^, 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    325 
F=l+2— 3=0 

Such  a  system  has  no  degrees  of  freedom.  This  means 
that  no  physical  condition,  pressure  or  temperature  can 
be  varied  without  destroying  a  phase,  so  that  such  a  sys- 
tem can  only  exist  in  equilibrium  at  one  fixed  tempera- 
ture, with  a  fixed  value  for  its  vapor-pressure. 

For  instance,  if  the  system  is  heated  above  the  fixed 
temperature,  ice  disappears  and  if  the  pressure  is  raised, 
vapor  is  condensed.  If  this  same  system  of  water  alone 
contains  but  two  phases,  for  instance,  liquid  and  vapor, 
F  =  1  +  2  — 2  =  1,  or  there  is  one  degree  of  freedom. 
In  such  a  system,  one  physical  condition  such  as  tempera- 
ture can  be  varied  independently,  but  only  one,  without 
destroying  a  phase.  For  instance,  the  temperature  may 
be  raised  or  lowered,  but  for  every  value  of  temperature 
there  is  a  corresponding  value  for  the  vapor  pressure. 
One  is  a  function  of  the  other.  If  both  values  are  varied 
independently,  one  phase  will  disappear,  either  vapor 
condensing  entirely  to  water  or  the  reverse.  Finally  if 
the  system  consists  of  one  phase  only,  as  water  vapor, 
F  =  2,  or  the  system  is  divariant,  which  means  that  at 
any  given  temperature  it  is  possible  for  vapor  to  exist  at 
varying  pressures. 

The  illustration  which  has  been  given  relates  to  physi- 
cal equilibrium,  but  the  rule  is  applicable  to  cases  involv- 
ing chemical  changes  as  well.  In  comparing  the 
phase-rule  with  the  law  of  mass  action,  it  will  be  noticed 
that  both  have  to  do  with  equilibrium.  The  great  advan- 
tage of  the  former  is  that  it  is  entirely  independent  of  the 
molecular  condition  of  the  substances  in  the  diiferent 
phases.  For  instance,  it  makes  no  difference  so  far  as 
the  application  of  the  rule  is  concerned,  whether  a  sub- 
stance in  solution  is  dissociated,  undissociated  or  com- 
bined with  the  solvent.  In  any  case,  the  solution 
constitutes  one  phase.  On  the  other  hand,  the  rule  is 
purely  qualitative,  giving  information  only  as  to  whether 
a  given  change  in  conditions  is  possible.  The  law  of 
mass  action  is  a  quantitative  expression  so  that  when  the 
value  of  the  constant  is  once  known,  the  change  can  be 
calculated  which  takes  place  in  the  entire  system  if  the 
concentration  of  one  substance  is  varied.  The  law,  how- 
ever, requires  a  knowledge  of  the  molecular  condition  of 


326  A  CENTURY  OF  SCIENCE 

the  reacting  substances,  which  may  be  uncertain  or  un- 
known, and  chiefly  on  this  account  it  has,  like  the  phase- 
rule,  often  only  a  qualitative  significance. 

The  phase  rule  has  served  as  a  most  valuable  means 
of  classifying  systems  in  equilibrium  and  as  a  guide  in 
determining  the  possible  conditions  under  which  such 
systems  can  exist.  As  illustrations  of  its  practical  appli- 
cation, van't  Hoff  used  it  as  an  underlying  principle  in 
his  investigations  on  the  conditions  under  which  salt 
deposits  have  been  formed  in  nature,  and  Rooseboom  was 
able  by  its  means  to  explain  the  very  complicated  rela- 
tions existing  in  the  alloys  of  iron  and  carbon  which  form 
the  various  grades  of  wrought  iron,  steel  and  cast  iron. 

Thermochemistry. — This  branch  of  chemistry  has  to 
do  with  heat  evolved  or  absorbed  in  chemical  reactions. 
It  is  important  chiefly  because  in  many  cases  it  furnishes 
the  only  measure  we  have  of  the  energy  changes  involved 
in  reactions.  To  a  great  extent,  it  dates  from  the  dis- 
covery by  Hess  in  1840  of  a  fundamental  law  which  states 
that  the  heat  evolved  in  a  reaction  is  the  same  whether  it 
takes  place  in  one  or  in  several  stages.  This  law  has 
made  it  possible  to  calculate  the  heat  values  of  a  large 
number  of  reactions  which  cannot  be  determined  by 
direct  experiment. 

Thermochemistry  has  been  developed  by  a  compara- 
tively few  men  who  have  contributed  a  surprisingly 
large  number  of  results.  Favre  and  Silbermann,  begin- 
ning shortly  after  1850,  improved  the  apparatus  for  cal- 
orimetric  determinations,  which  is  called  the  calorimeter, 
and  published  many  results.  At  about  the  same  time 
Julius  Thomsen,  and  in  1873  Berthelot,  began  their 
remarkable  series  of  publications  which  continued  until 
recently.  Thomsen 's  investigations  were  published  in 
1882  in  4  volumes.  It  is  probably  safe  to  say  that  the 
greater  part  of  the  data  of  thermochemistry  was  obtained 
by  these  two  investigators.  The  bomb  calorimeter,  an 
apparatus  for  determining  heat  values  by  direct  combus- 
tion, was  developed  by  Berthelot.  The  recent  work  of 
Mixter  at  Yale,  published  in  the  Journal,  and  of  Rich- 
ards at  Harvard  should  be  mentioned  particularly. 
Mixter 's  work  in  this  field  began  in  1901  (12,  347). 
Using  an  improved  bomb  calorimeter,  he  has  developed  a 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    327 

method  of  determining  the  heats  of  formation  of  oxides 
by  combustion  with  sodium  peroxide.  By  this  same 
method  as  well  as  by  direct  combustion  in  oxygen,  he  has 
obtained  results  which  appear  to  equal  or  excel  in  accu- 
racy any  which  have  ever  been  obtained  in  his  field  of 
work.  Richards  ^s  work  has  consisted  largely  of  improve- 
ments in  apparatus.  He  developed  the  so-called  adia- 
batic  calorimeter  which  practically  eliminates  one  of  the 
chief  errors  in  thermal  work  caused  by  the  heating  or 
cooling  effect  of  the  surroundings.  This  modification  is 
being  generally  adopted  where  extremely  accurate  work 
is  required. 

Organic  Cheinistry, 

One  hundred  years  ago  qualitative  tests  for  a  few 
organic  compounds  were  known,  the  elements  usually 
occurring  in  them  were  recognized,  and  some  of  them  had 
been  analyzed  quantitatively,  but  organic  chemistry  was 
far  less  advanced  than  inorganic,  and  almost  the  whole  of 
its  enormous  development  has  taken  place  during  our 
period. 

Berzelius  made  a  great  advance  in  the  subject  by  estab- 
lishing the  fact,  which  had  been  doubted  previously,  that 
the  elements  in  organic  compounds  are  combined  in  con- 
stant, definite  proportions.  In  1823  Liebig  brought  to 
light  the  exceedingly  important  fact  of  isomerism  by 
showing  that  silver  fulminate  had  the  same  percen- 
tage composition  as  silver  cyanate,  a  compound  of  very 
different  properties.  Isomeric  compounds  with  identical 
molecular  weight  as  well  as  the  same  composition  have 
since  been  found  in  very  many  cases,  and  they  have 
played  a  most  important  part  in  determining  the 
arrangements  of  atoms  in  molecules.  They  have  been 
found  to  be  very  numerous  in  many  cases.  For  instance, 
three  pentanes  with  the  formula  C5H12  are  known,  all 
that  are  possible  according  to  theory,  and  in  each  case 
the  structure  of  the  molecule  has  been  established.  On 
theoretical  grounds  it  has  been  calculated  that  802 
isomeric  compounds  with  the  formula  C13H28  are  possi- 
ble, while  with  more  complex  formulas  the  numbers  of 
isomers  may  be  very  much  greater. 


328  A  CENTURY  OF  SCIENCE 

A  particularly  interesting  case  of  isomerism  was 
observed  by  Wohler  in  1828,  when  he  found  that  ammo- 
nium cyanate  changes  spontaneously  into  urea 

(NH^CNO >N,H,CO). 

This  was  the  first  synthesis  of  an  organic  compound  from 
inorganic  material,  and  it  overthrew  the  prevailing  view 
that  vital  forces  were  essential  in  the  formation  of 
organic  substances.  A  great  many  natural  organic  com- 
pounds have  been  made  artificially  since  that  time,  and 
some  of  them,  such  as  artificial  alizarin,  indigo,  oil  of 
wintergreen,  and  vanillin,  have  more  or  less  fully 
replaced  the  natural  products.  The  preparation  of  a 
vast  number  of  compounds  not  known  in  nature,  many  of 
which  are  of  practical  importance  as  medicines,  dyes, 
explosives,  etc.,  has  been  another  great  achievement  of 
organic  chemistry. 

The  development  of  our  present  formulas  for  organic 
compounds,  by  means  of  which  in  many  cases  the  rela- 
tive positions  of  the  atoms  can  be  shown  with  the  great- 
est confidence,  has  been  gradual.  Formulas  based  on  the 
dualistic  idea  of  Berzelius  were  used  for  some  time,  type 
formulas,  with  the  employment  of  compound  radicals, 
came  later,  the  substitution  of  atoms  or  groups  of  atoms 
for  others  in  chemical  reactions  came  to  be  recognized, 
but  one  of  the  most  important  steps  was  the  recognition 
of  the  quadrivalence  of  carbon  and  the  general  applica- 
tion of  valency  to  atoms  by  Kekule  about  1858.  This  led 
directly  to  the  use  of  modern  structural  formulas  which 
have  been  of  the  greatest  value  in  the  theoretical  inter- 
pretation of  organic  reactions.  It  was  Kekule  also  who 
proposed  the  hexagonal  ring-formula  for  benzene,  GJIq, 
which  led  to  exceedingly  important  theoretical  and  prac- 
tical developments.  The  details  of  the  formulas  for 
many  other  rings  and  complex  structures  have  been  estab- 
lished since  that  time,  and  there  is  no  doubt  that  the 
remarkable  achievements  in  organic  chemistry  during  the 
past  sixty  years  have  been  much  facilitated  by  the  use  of 
these  formulas. 

Many  important  researches  in  organic  chemistry  have 
been  carried  out  in  the  United  States,  and  the  activity  in 
this  direction  has  greatly  increased  in  recent  years.     In 


ONE  HUNDRED  YEAES  OF  CHEMISTRY    329 

this  connection  the  large  amount  of  work  of  this  kind 
accomplished  in  the  Sheffield  Laboratory,  at  present 
under  the  guidance  of  Professor  T.  B.  Johnson,  should  be 
mentioned. 

It  has  happened  that  comparatively  few  publications 
on  organic  chemistry  have  appeared  in  the  Journal,  but 
it  may  be  stated  that  the  preparation  of  chloroform  and 
its  physiological  effects  were  described  by  Guthrie  (21, 
64,  1832).  Unknown  to  him,  it  had  been  prepared  by 
Souberain,  a  French  chemist,  the  previous  year,  but  the 
former  was  the  first  to  describe  its  physiological  action. 
Silliman  gave  a  sample  to  Doctor  Eli  Ives  of  the  Yale 
Medical  School,  who  used  it  to  relieve  a  case  of  asthma. 
This  was  the  first  use  of  chloroform  in  medical  practice 
(21,  405,  1832).  Guthrie  also  described  in  the  Journal 
(21,  284,  1832)  his  new  process  for  converting  potato 
starch  into  glucose,  a  method  which  is  essentially  the 
same  as  that  used  to-day  in  converting  cornstarch  into 
glucose.  Lawrence  Smith  (43,  301,  1842  et  seq.),  Hors- 
ford  (3,  369,  1847  et  seq.),  Sterry  Hunt  (7,  399,  1849), 
Carey  Lea  (26,  379, 1858  et  seq.),  Remsen  (5,  179,  1873  et 
seq.),  and  others  have  contributed  articles  on  organic 
chemistry. 

Agricultural  Chemistry, 

Until  near  the  middle  of  the  nineteenth  century,  it  was 
believed  that  plants,  like  animals,  used  organic  matter  for 
food,  and  depended  chiefly  upon  the  humus  of  the  soil 
for  their  growth.  This  view  was  held  even  long  after  it 
was  known  that  plant  leaves  absorb  carbon  dioxide  and 
give  off  oxygen,  and  after  the  ashes  of  plants  had  been 
accurately  analyzed. 

This  incorrect  view  was  overthrown  by  the  celebrated 
German  chemist,  Liebig,  who  made  many  investigations 
upon  the  subject,  and,  properly  interpreting  previous 
knowledge,  published  a  book  in  1840  upon  the  applica- 
tion of  chemistry  to  agriculture  and  physiology  in  which 
he  maintained  that  the  nutritive  materials  of  all  green 
plants  are  inorganic  substances,  namely,  carbon  dioxide, 
water,  ammonia  (nitrates),  sulphates,  phosphates,  silica, 
lime,  magnesia,  potash,  iron,  and  sometimes  common  salt. 
He  drew  the  vastly  important  conclusion  that  the  effective 


330  A  CENTURY  OF  SCIENCE 

fertilization  of  soils  depends  upon  replenishing  the 
inorganic  substances  that  have  been  exhausted  by  the 
crops. 

The  fundamental  principles  set  forth  by  Liebig  have 
been  confirmed,  and  it  has  been  found  that  the  fertilizing 
constituents  most  commonly  lacking  in  soils  are  nitrogen 
compounds,  phosphates,  and  potassium  salts,  so  that 
these  have  formed  the  important  constituents  of  artificial 
fertilizers.  Liebig  himself  found  that  humus  is  valuable 
in  soils,  because  it  absorbs  and  retains  the  soluble  salts. 

The  foundation  established  by  Liebig  in  regard  to  arti- 
ficial fertilizers  has  led  to  an  enormous  application  of 
these  materials,  much  to  the  advantage  of  the  world's 
food-supply. 

It  was  Liebig 's  belief,  in  accordance  with  the  prevail- 
ing views,  that  decay  and  putrefaction  as  well  as 
alcoholic  and  other  fermentations  were  spontaneous 
processes,  and  when  the  eminent  French  chemist,  Pas- 
teur, in  1857,  explained  fermentation  as  directly  caused 
by  yeast,  an  epoch-making  discovery  which  led  to  the 
explanation  of  decay  and  putrefaction  by  bacterial  action 
and  to  the  germ-theory  of  disease,  the  explanation  was 
violently  opposed  by  Liebig  and  other  German  chemists. 
Pasteur's  view  prevailed,  however,  and  since  that  time 
it  has  been  found  that  various  kinds  of  bacteria  are 
responsible  for  the  formation  of  ammonia  from  nitro- 
genous organic  matter  and  also  for  the  change  of  ammo- 
nia into  the  nitrates  that  are  available  as  plant-food. 

The  long-debated  question  as  to  the  availability  of 
atmospheric  nitrogen  for  plant-food  was  settled  in  1886 
by  the  discovery  of  Hellriegel  that  bacteria  contained  in 
nodules  on  the  roots,  especially  of  leguminous  plants,  are 
capable  of  bringing  nitrogen  into  combination  and  fur- 
nishing it  to  the  plants. 

No  more  than  an  allusion  can  be  made  to  agricultural 
experiment  stations  where  soils,  fertilizers,  foods  and 
other  products  are  examined,  and  where  other  problems 
connected  with  agriculture  are  studied. 

The  late  S.  W.  Johnson  of  Yale  studied  with  Liebig 
and  subsequently  did  much  service  for  agricultural  chem- 
istry in  this  country,  by  his  investigations,  his  teaching, 
and  his  writings.     His  book,  **IIow  Crops  Grow,"  pub- 


ONE  HUNDEED  YEARS  OF  CHEMISTRY    331 

lished  in  1868,  gave  an  excellent  account  of  the  principles 
of  agricultural  chemistry.  He  did  much  to  bring  about 
the  establishment  of  agricultural  experiment  stations  in 
this  country,  and  for  a  long  time  he  was  the  director  of 
the  Connecticut  Station. 

In  the  Journal,  as  early  as  1827,  Amos  Eaton  (12,  370) 
published  a  simple  method  for  the  mechanical  analysis 
of  soils  to  determine  their  suitability  for  wheat-culture, 
and  Hilgard,  between  1872  and  1874,  described  an  elab- 
orate study  of  soil-analysis.  J.  P.  Norton,  a  Yale 
professor,  in  1847  (3,  322)  published  an  investigation 
on  the  analysis  of  the  oat,  which  was  awarded  a  prize  of 
fifty  sovereigns  by  a  Scotch  agricultural  society,  while 
Johnson,  Atwater,  and  others  have  contributed  articles 
on  the  analysis  of  various  farm  products. 

Industrial  Acids  and  Alkalies, 

One  hundred  years  ago  sulphuric  acid  was  manufac- 
tured on  a  comparatively  very  small  scale  in  lead 
chambers.  In  1818,  an  English  manufacturer  of  the 
acid  introduced  the  modern  feature  of  using  pyrites  in 
the  place  of  brimstone,  while  the  Gay-Lussac  tower  in 
1827  and  the  Glover  tower  in  1859  began  to  be  applied  as 
great  improvements  in  the  chamber  process.  Within 
about  twenty  years  the  contact  process,  employing  plat- 
inized asbestos,  has  replaced  the  old  chamber  process  to 
a  large  extent.  It  has  the  advantage  of  producing  the 
concentrated  acid,  or  the  fuming  acid,  directly. 

During  our  period  the  manufacture  of  sulphuric  acid 
has  increased  enormously.  Very  large  quantities  of  it 
have  been  used  in  connection  with  the  Leblanc  soda  pro- 
cess in  its  rapid  development.  It  came  to  be  employed 
extensively  for  absorbing  ammonia  in  the  illuminating- 
gas  industry,  which  was  in  its  infancy  one  hundred  years 
ago.  New  industries  such  as  the  manufacture  of  *  *  super- 
phosphates''  as  artificial  fertilizers,  the  refining  of  petro- 
leum, the  manufacture  of  artificial  dyestuffs  and  many 
other  modern  chemical  products  have  greatly  increased 
the  demand  for  it,  while  its  employment  in  the  production 
of  nitric  and  other  acids,  and  for  many  other  purposes 
not  already  mentioned,  has  been  very  great. 

The   manufacture    of   nitric    acid   has    been   greatly 


332  A  CENTURY  OF  SCIENCE 

extended  during  our  period  on  account  of  its  employment 
for  producing  explosives,  artificial  dyestuffs,  and  for 
many  other  purposes.  Chile  saltpeter  became  available 
for  making  it  about  1852.  This  acid  has  been  manufac- 
tured recently  from  atmospheric  nitrogen  and  oxygen  by 
combining  them  by  the  aid  of  powerful  electric  dis- 
charges. This  process  has  been  used  chiefly  in  Norway 
where  water-power  is  abundant,  as  it  requires  a  large 
expenditure  of  energy.  A  still  more  recent  method  for 
the  production  of  nitric  acid  depends  upon  the  oxidation 
of  ammonia  by  air  with  the  aid  of  a  contact  substance, 
such  as  platinized  asbestos. 

The  production  of  ammonia,  which  was  very  small  a 
hundred  years  ago,  has  been  vastly  increased  in  connec- 
tion with  the  development  of  the  illuminating-gas  indus- 
try and  the  employment  of  by-product  coke  ovens.  This 
substance  is  very  extensively  used  in  refrigerating 
machines  and  also  in  a  great  many  chemical  operations, 
including  the  Solvay  soda-process.  Ammonium  salts 
are  of  great  importance  also  as  fertilizers  in  agriculture. 
The  conversion  of  atmospheric  nitrogen  into  ammonia 
on  a  commercial  scale  is  a  recent  achievement.  It  has 
been  accomplished  by  heating  calcium  carbide,  an  elec- 
tric-furnace product  made  from  lime  and  coke,  with  nitro- 
gen gas,  thus  producing  calcium  cyanamide,  and  then 
treating  this  cyanamide  with  water  under  proper  condi- 
tions. Another  method  devised  by  Haber  consists  in 
directly  combining  nitrogen  and  hydrogen  gases  under 
high  pressure  with  the  aid  of  a  contact  substance. 

Leblanc's  method  for  obtaining  sodium  carbonate  from 
sodium  chloride  by  first  converting  the  latter  into  the 
sulphate  by  means  of  sulphuric  acid  and  then  heating  the 
sulphate  with  lime  and  coal  in  a  furnace  was  invented 
as  early  as  1791,  but  it  was  not  rapidly  developed  and  did 
not  gain  a  foothold  in  England  until  1826  on  account  of  a 
high  duty  on  salt  up  to  that  time.  Afterwards  the 
process  flourished  greatly  in  connection  with  the  sul- 
phuric acid  industry  upon  which  it  depended,  and  with 
the  bleaching-powder  industry  which  utilized  the  hydro- 
chloric acid  incidentally  produced  by  it,  and,  of  course, 
in  connection  with  soap  manufacture  and  many  other 
industries  in  which  the  soda  itself  was  employed. 


ONE  HUNDRED  YEARS  OF  CHEMISTRY    333 

About  1866  the  Solvay  process  appeared  as  a  rival  to 
the  Leblanc  process.  This  depends  upon  the  precipita- 
tion of  sodium  bicarbonate  from  salt  solutions  by  means 
of  carbon  dioxide  and  ammonia,  with  the  subsequent 
recovery  of  the  ammonia.  It  has  displaced  the  older 
process  to  a  large  extent,  and  it  is  carried  on  extensively 
in  this  country,  for  instance,  at  Syracuse,  New  York. 

Other  processes  for  soda  depend  upon  the  electrolysis 
of  sodium  chloride  solutions.  In  this  case  caustic  soda 
and  chlorine  are  the  direct  products,  and  the  chlorine 
thus  produced  and  liquified  by  pressure  in  steel  cylinders, 
has  become  an  important  commercial  article. 

In  earlier  times  wood-ashes  were  the  source  of  potash 
and  potassium  salts.  Wurtz  in  the  Journal  (10,  326, 
1850)  suggested  the  availability  of  New  Jersey  green- 
sand  as  a  source  of  potash  and  showed  how  this  mineral 
could  be  decomposed,  but  it  does  not  appear  that  this 
mineral  has  ever  been  utilized  for  the  purpose.  About 
1861  the  German  potash-salt  deposits  began  to  be  devel- 
oped, and  these  have  since  become  the  chief  source  of 
this  material.  At  present  many  efforts  are  being  made 
to  obtain  potassium  compounds  from  other  sources,  such 
as  brines,  cement-kiln  dust,  and  feldspar  and  other  min- 
erals but  thus  far  the  results  have  not  satisfied  the 
demand. 

Conclusion* 

This  account  of  chemical  progress  has  given  only  a 
limited  view  of  small  portions  of  the  subject,  because  the 
amount  of  available  material  is  so  vast  in  comparison 
with  the  space  allowed  for  its  presentation.  Since  the 
Journal  has  published  comparatively  little  organic  chem- 
istry, it  was  decided  to  make  room  for  a  better  presenta- 
tion of  other  things  by  giving  only  a  brief  discussion  of 
this  exceedingly  active  and  important  branch  of  the 
science.  For  similar  reasons  industrial  and  metallurgi- 
cal chemistry,  and  other  branches  besides,  in  spite  of 
their  great  growth  and  importance,  have  been  neglected, 
except  for  some  incidental  references  to  them,  and  some 
account  of  a  few  of  the  more  important  industrial 
chemicals. 

It  appears  that  we  have  much  reason  to  be  proud  of  the 

21 


334:  A  CENTURY  OF  SCIENCE 

advances  in  chemistry  that  have  been  made  during  the 
JournaPs  period,  and  of  the  part  that  the  Journal  has 
taken  in  connection  with  them,  and  there  seems  to  be  no 
doubt  that  this  progress  has  not  diminished  during  more 
recent  times. 

The  present  tendency  of  chemical  research  is  evidently 
towards  a  still  greater  development  of  organic  chemis- 
try, and  an  increased  application  of  physics  and  mathe- 
matics to  chemical  theory  and  practice. 

The  very  great  improvements  that  have  been  made  in 
chemical  education,  both  in  the  number  of  students  and 
the  quality  of  instruction,  during  the  period  under  dis- 
cussion, and  particularly  in  rather  recent  times,  gives 
promise  for  excellent  future  progress. 


Note, 

^  It  appears  that  the  most  accurate  experimental  demonstration  ever  made 
of  this  law  was  that  of  E,  W.  Morley,  published  in  the  Journal  (41,  220, 
276,  1891).  He  showed  that  2-0002  volimies  of  hydrogen  combine  with  one 
volume  of  oxygen. 


XI 

A  CENTURY'S  PROGRESS  IN  PHYSICS 

By  LEIGH  PAGE 

DYNAMICS. — At  the  beginning  of  the  nineteenth 
century  mechanics  was  the  only  major  branch  of 
physical  science  which  had  attained  any  consider- 
able degree  of  development.  Two  centuries  earlier, 
Galileo  ^s  experiments  on  the  rate  of  fall  of  iron  balls 
dropped  from  the  top  of  the  Leaning  Tower  of  Pisa,  had 
marked  the  origin  of  dynamics.  He  had  easily  disproved 
the  prevalent  idea  that  even  under  conditions  where  air 
resistance  is  negligible  heavy  bodies  would  fall  more 
rapidly  than  light  ones,  and  further  experiments  had  led 
him  to  conclude  that  the  increase  in  velocity  is  propor- 
tional to  the  time  elapsed,  and  not  to  the  distance 
traversed,  as  he  had  at  first  supposed.  Less  than  a 
century  later  Newton  had  formulated  the  laws  of  motion 
in  the  same  words  in  which  they  are  given  to-day.  These 
laws  of  motion,  coupled  with  his  discovery  of  the  law  of 
universal  gravitation,  had  enabled  him  to  correlate  at 
once  the  planetary  notions  which  had  proved  so  puzzling 
to^  his  predecessors.  His  success  gave  a  tremendous 
stimulus  to  the  development  and  extension  of  the  funda- 
mental dynamical  principles  that  he  had  brought  to  light, 
which  culminated  in  the  work  of  the  great  French  mathe- 
maticians, Lagrange  and  Laplace,  a  little  over  a  hundred 
years  ago. 

Newton's  laws  of  motion,  it  must  be  remembered, 
apply  only  to  a  particle,  or  to  those  bodies  which  can  be 
treated  as  particles  in  the  problem  under  consideration. 
In  his  ^'Mecanique  Analytique"  Lagrange  extended 
these  principles  so  as  to  make  it  possible  to  treat  the 
motion  of  a  connected  system  by  a  method  almost  as  sim- 
ple  as   that   contained  in   the   second  law   of  motion. 


336  A  CENTURY  OF  SCIENCE 

Instead  of  three  scalar  equations  for  each  of  the  innumer- 
ably large  number  of  particles  involved,  he  showed  how 
to  reduce  the  ordinary  dynamical  equations  to  a  number 
equal  to  that  of  the  degrees  of  freedom  of  the  system. 
This  is  made  possible  by  a  combination  of  d'Alembert's 
principle,  which  eliminates  the  forces  due  to  the  connec- 
tions between  the  particles,  and  the  principle  of  virtual 
work,  which  confines  the  number  of  equations  to  the  num- 
ber of  possible  independent  displacements.  The  aim  of 
Lagrange  was  to  make  dynamics  into  a  branch  of 
analysis,  and  his  success  may  be  inferred  from  the  fact 
that  not  a  single  diagram  or  geometrical  figure  is  to  be 
found  in  his  great  work. 

Celestial  Mechanics. — Almost  simultaneously  with  the 
publication  of  the  ^^Mecanique  Analytique''  appeared 
Laplace's  ^^Mecanique  Celeste."  Laplace's  avowed 
aim  was  to  offer  a  complete  solution  of  the  great 
dynamical  problem  involved  in  the  solar  system,  taking 
into  account,  in  addition  to  the  effect  of  the  sun's  gravi- 
tational field,  those  perturbations  in  the  motion  of  each 
planet  caused  by  the  approach  and  recession  of  its 
neighbors.  So  successful  was  his  analysis  of  planetary 
motions  that  his  contemporaries  believed  that  they  were 
not  far  from  a  complete  explanation  of  the  world  on 
mechanical  principles.  Laplace  himself  was  undoubt- 
edly convinced  that  nothing  was  needed  beyond  a 
knowledge  of  the  masses,  positions,  and  initial  velocities 
of  every  material  particle  in  the  universe  in  order  to 
completely  predetermine  all  subsequent  motion. 

The  greatest  triumph  of  these  dynamical  methods  was 
to  come  half  a  century  later.  The  planet  Uranus,  dis- 
covered in  1781  by  the  elder  Herschel,  was  at  that  time 
the  farthest  known  planet  from  the  sun.  But  the  orbit 
of  Uranus  was  subject  to  some  puzzling  variations. 
After  sifting  all  the  known  causes  of  these  disturbances^ 
Leverrier  in  France  and  Adams  in  England  independ- 
ently reached  the  conclusion  that  another  planet  still 
more  remote  from  the  sun  must  be  responsible,  and  com- 
puted its  orbit.  Leverrier  communicated  to  Galle  of 
Berlin  the  results  of  his  calculations,  and  during  the  next 
few  days  the  German  astronomer  discovered  Neptune 
within  one  degree  of  its  predicted  position ! 


V.  ^  yhu..^^tz;z^ 


A  CENTURY'S  PROGRESS  IN  PHYSICS     337 

We  shall  mention  but  one  other  achievement  of  the 
methods  of  celestial  mechanics.  Those  visitors  of  the 
skies,  the  comets,  which  become  so  prominent  only  to  fade 
away  and  vanish  perhaps  forever,  had  interested  astron- 
omers from  the  earliest  times.  Soon  after  the  discovery 
of  the  law  of  gravitation,  Newton  had  worked  out  a 
method  by  which  the  elements  of  a  comet's  orbit  can  be 
computed  from  observations  of  its  position.  It  was 
found  that  the  great  majority  of  these  bodies  move  in 
nearly  parabolic  paths  and  only  a  few  in  ellipses.  Of  the 
latter  the  most  prominent  is  the  brilliant  comet  first 
observed  by  Halley  in  1681.  It  has  reappeared  regu- 
larly at  intervals  of  seventy-six  years ;  the  last  appear- 
ance in  the  spring  of  1910  is  no  doubt  well  remembered 
by  the  reader.  Kant  had  considered  comets  to  be 
formed  by  condensing  solar  nebulae,  whereas  Laplace  had 
maintained  that  they  originate  in  matter  which  is  scat- 
tered throughout  stellar  space  and  has  no  connection 
with  the  solar  system.  A  study  of  the  distribution  of 
inclinations  of  comet  orbits  by  H.  A.  Newton  (16,  165, 
1878)  of  New  Haven  substantiated  Laplace's  hypothesis, 
and  led  to  the  conclusion  that  the  periodic  comets  have 
been  captured  by  the  attraction  of  those  planets  near  to 
which  they  have  passed.  Of  these  comets  a  number 
have  comparatively  short  periods,  and  are  found  to  have 
orbits  which  are  in  general  only  slightly  inclined  to  those 
of  the  planets,  and  are  traversed  in  the  same  direction. 
Moreover,  the  fact  that  the  orbit  of  each  of  these  comets 
comes  very  close  to  that  of  Jupiter  made  it  seem  probable 
that  they  have  been  attached  to  the  solar  system  by  the 
attraction  of  this  planet.  Further  confirmation  of  this 
hypothesis  was  furnished  by  H.  A.  Newton's  (42, 183  and 
482,  1891)  explanation  of  the  small  inclination  of  their 
orbits  and  the  scarcity  of  retrograde  motions  among 
them. 

In  1833  occurred  one  of  the  greatest  meteoric  showers 
of  history.  Olmstead  (26,  132,  1834)  and  Twining  (26, 
320,  1834)  of  New  Haven  noticed  that  these  shooting 
stars  traverse  parallel  paths,  and  were  the  first  to  sug- 
gest that  they  must  be  moving  in  swarms  in  a  permanent 
orbit.  From  an  examination  of  all  accessible  records, 
H.  A.  Newton  (37,  377,  1864;  38,  53,  1864)  was  able  to 


338  A  CENTURY  OF  SCIENCE 

show  that  meteoric  showers  are  common  in  November, 
and  of  particular  intensity  at  intervals  of  33  or  34  years. 
He  confidently  predicted  a  great  shower  for  Nov.  13th, 
1866,  which  not  only  actually  occurred  but  was  followed 
by  another  a  year  later,  showing  that  the  meteoric  swarm 
extended  so  far  as  to  require  two  years  to  cross  the 
earth's  orbit.  H.  A.  Newton  (36,  1,  1888)  in  America 
and  Adams  in  England  took  up  the  study  of  meteoric 
orbits  with  great  interest,  and  the  former  concluded  that 
these  orbits  are  in  every  sense  similar  to  those  of  the 
periodic  comets,  implying  that  a  swarm  of  meteors 
originates  in  the  disintegration  of  a  comet.  In  fact 
Schiaparelli  actually  identified  the  orbit  of  the  Perseids, 
or  August  meteors,  with  Tuttle's  comet  of  1862,  and 
shortly  after  the  orbit  of  the  Leonids,  or  November 
meteors,  was  found  to  be  the  same  as  that  of  TempePs 
comet. 

Electromagnetism. — During  the  eighteenth  century 
much  interest  had  been  manifested  in  the  study  of  elec- 
trostatics and  magnetism.  Du  Fay,  Cavendish,  Michel! 
and  Coulomb  abroad  and  Franklin  in  America  had  sub- 
jected to  experimental  investigation  many  of  the  phe- 
nomena of  one  or  both  of  these  sciences,  and  in  the  early 
years  of  the  nineteenth  century  Poisson  developed  to  a 
remarkable  extent  the  analytical  consequences  of  the  law 
of  force  which  experiment  had  revealed.  Both  Laplace 
and  he  made  much  use  of  the  function  to  which  Green 
gave  the  name  *  ^potential"  in  1828,  and  which  is  such  a 
powerful  aid  in  solving  problems  involving  magnetism 
or  electricity  at  rest. 

Meantime  electric  currents  had  been  brought  under  the 
hand  of  the  experimenter  by  the  discoveries  of  Galvani 
and  Volta.  Large  numbers  of  cells  were  connected  in 
series,  and  interest  seemed  to  lie  largely  in  producing 
brilliant  sparks  or  fusing  metals  by  means  of  a  heavy 
current.  Hare  (3,  105,  1821)  of  the  University  of  Penn- 
sylvania constructed  a  battery  consisting  of  two  troughs 
of  forty  cells  each,  so  arranged  that  the  coppers  and 
zincs  can  be  lowered  simultaneously  into  the  acid  and 
large  currents  obtained  before  polarization  has  a  chance 
to  interfere.     This   **deflagrator'*  was  used  to  ignite 


A  CENTURY  ^S  PROGRESS  IN  PHYSICS     339 

charcoal  in  the  circuit,  or  melt  fine  wires,  and  was  for 
some  time  the  most  powerful  arrangement  of  its  kind. 
That  *^ galvanism''  is  something  quite  different  from 
static  electricity  was  the  opinion  of  many  investigators ; 
Hare  considered  the  heat  developed  to  be  the  distinguish- 
ing mark  of  the  electric  current.  He  says:  **It  is 
admitted  that  the  action  of  the  galvanic  fluid  is  upon  or 
between  atoms ;  while  mechanical  electricity  when  unco- 
erced, acts  only  upon  masses.  This  difference  has  not 
been  explained  unless  by  my  hypothesis,  in  which  caloric, 
of  which  the  influence  is  only  exerted  between  atoms, 
is  supposed  to  be  a  principal  agent  in  galvanism.'' 

Questioning  minds  were  beginning  to  suspect  that 
there  must  be  some  connection  between  electricity  and 
magnetism.  For  lightning  had  been  known  to  make 
magnets  of  steel  knives  and  forks,  and  Franklin  had  mag- 
netized a  sewing  needle  by  the  discharge  from  a  Leyden 
jar.  Finally  Oersted  of  Copenhagen  undertook  syste- 
matic investigation  of  the  effect  of  electricity  on  the  mag- 
netic needle.  His  researches  were  without  result  until 
during  the  course  of  a  series  of  lectures  on  **  Electricity, 
Galvanism,  and  Magnetism"  delivered  during  the  winter 
of  1819-20  it  occurred  to  him  to  investigate  the  action  of 
an  electric  current  on  a  magnetic  needle.  At  first  he 
placed  the  wire  bearing  the  current  at  right  angles  to  the 
needle,  with,  of  course,  no  result;  then  it  occurred  to 
him  to  place  it  parallel.  A  deflection  was  observed,  for 
to  his  surprise  the  needle  insisted  on  turning  until  per- 
pendicular to  the  wire. 

Oersted's  discovery  that  an  electric  current  exerts  a 
couple  on  a  magnetic  needle  was  followed  a  few  months 
later  by  Ampere's  demonstration  before  the  French 
Academy  that  two  currents  flowing  in  the  same  direction 
attract  each  other,  while  two  in  opposite  directions  repel. 
The  story  goes  that  a  critic  attempted  to  belittle  this  dis- 
covery by  remarking  that  as  it  was  known  that  two  cur- 
rents act  on  one  and  the  same  magnet,  it  was  obvious 
that  they  would  act  upon  each  other.  Whereupon  Arago 
arose  to  defend  his  friend.  Drawing  two  keys  out  of 
his  pocket  he  said,  *^Each  of  these  keys  attracts  a  mag- 
net; do  you  believe  that  they  therefore  attract  each 
other?" 


340  A  CENTURY  OF  SCIENCE 

A  few  years  later  Ampere  showed  how  to  express 
quantitatively  the  force  between  current  elements,  and 
indeed  developed  to  a  considerable  degree  the  equiva- 
lence between  a  closed  circuit  carrying  a  current  and  a 
magnetic  shell.  So  convincing  was  his  analysis  and  so 
thorough  his  discussion  of  the  subject,  that  Maxwell  said 
of  this  memoir  half  a  century  later,  *^The  whole,  theory 
and  experiment,  seems  as  if  it  had  leaped,  full  grown  and 
full  armed,  from  the  brain  of  the  ^Newton  of  electricity.' 
It  is  perfect  in  form  and  unassailable  in  accuracy;  and 
it  is  summed  up  in  a  formula  from  which  all  the  phe- 
nomena may  be  deduced,  and  which  must  always  remain 
the  cardinal  formula  of  electrodynamics." 

Shortly  afterwards  the  dependence  of  a  current  on  the 
conductivity  of  the  wire  used  and  the  grouping  of  cells 
employed,  was  made  clear  by  the  work  of  Ohm.  Many 
of  his  results  were  obtained  independently  by  Joseph 
Henry  (19,  400,  1831)  of  the  Albany  Academy,  who 
described  in  1831  a  powerful  electromagnet  in  which  a 
great  many  coils  of  wire  insulated  with  silk  were  wound 
around  an  iron  core  and  connected  in  parallel  with  a  sin- 
gle cell.  He  remarks  in  this  paper  that  with  long  wires, 
as  in  the  telegraph,  many  cells  arranged  in  series  should 
be  used,  whereas  for  several  short  wires  connected  in 
parallel  a  single  cell  with  large  plates  is  more  efficient. 

Current  Induction. — Impressed  by  the  fact  that  elec- 
tric charges  have  the  power  of  inducing  other  charges 
on  neighboring  conductors  without  coming  into  contact 
with  them,  Faraday  was  engaged  in  investigating  the 
possibility  of  an  analogous  phenomenon  in  the  case  of 
electric  currents.  His  idea  at  first  seems  to  have  been 
that  a  current  should  induce  another  current  in  any 
closed  conducting  circuit  which  happens  to  be  in  its 
vicinity.  Experiment  readily  showed  the  falsity  of  this 
conception,  but  a  brief  deflection  of  the  galvanometer  in 
the  secondary  circuit  was  noticed  at  the  instant  of  mak- 
ing and  breaking  the  current  in  the  primary.  Further 
experiments  showed  that  thrusting  a  permanent  steel 
magnet  into  a  coil  connected  to  a  galvanometer  caused 
the  needle  to  deflect.  In  fact  Faraday's  report  to  the 
Royal  Society  on  November  24th,  1831,  contains  a  com- 


A  CENTURY'S  PROGRESS  IN  PHYSICS     341 

plete  account  of  all  experimental  methods  available  for 
inducing  a  current  in  a  closed  circuit. 

While  Faraday  is  entitled  to  credit  for  the  discovery  of 
current  induction  by  virtue  of  the  priority  of  his  publica- 
tion, it  must  not  pass  unnoticed  that  Henry  obtained 
many  of  the  same  experimental  results  independently 
and  some  even  earlier.  Henry  was  at  this  time  instruc- 
tor in  mathematics  at  the  Albany  Academy,  and  seven 
hours  of  teaching  a  day  made  it  well-nigh  impossible  to 
carry  on  original  research  except  during  the  vacation 
month  of  August.  As  early  as  the  summer  of  1830  he 
had  wound  30  feet  of  copper  wire  around  the  armature 
of  a  horseshoe  electromagnet  and  connected  it  to  a  gal- 
vanometer. When  the  magnet  was  excited,  a  momen- 
tary deflection  was  observed.  **I  was,  however,  much 
surprised,"  he  says,  **to  see  the  needle  suddenly 
deflected  from  a  state  of  rest  to  about  20°  to  the  east,  or 
in  a  contrary  direction,  when  the  battery  was  withdrawn 
from  the  acid,  and  again  deflected  to  the  west  when 
it  was  re-immersed."  In  addition  a  deflection  was 
obtained  by  detaching  the  armature  from  the  magnet, 
or  by  bringing  it  again  into  contact.  Had  the  results  of 
these  experiments  been  published  promptly,  America 
would  have  been  entitled  to  credit  for  the  most  import- 
ant discovery  of  the  greatest  of  England's  many  great 
experimenters.  But  Henry  desired  first  to  repeat  his 
experiments  on  a  larger  scale,  and  while  new  magnets 
were  being  constructed,  the  news  of  Faraday's  discovery 
arrived.  This  occasioned  hasty  publication  of  the  work 
already  done  in  an  appendix  to  volume  22,  1832,  of  the 
Journal. 

At  almost  the  same  time  Henry  made  another  import- 
ant discovery  and  this  time  he  was  anticipated  by  no 
other  investigator  in  making  public  his  results.  In  the 
paper  already  referred  to  he  describes  the  phenomenon 
known  to-day  as  self-induction.  *^When  a  small  battery 
is  moderately  excited  by  diluted  acid  and  its  poles,  which 
must  be  terminated  by  cups  of  mercury,  are  connected  by 
a  copper  wire  not  more  than  a  foot  in  length,  no  spark 
is  perceived  when  the  connection  is  either  formed  or 
broken;  but  if  a  wire  thirty  or  forty  feet  long  be  used, 


342  A  CENTURY  OF  SCIENCE 

instead  of  the  short  wire,  though  no  spark  will  be  per- 
ceptible when  the  connection  is  made,  yet  when  it  is 
broken  by  drawing  one  end  of  the  wire  from  its  cup  of 
mercury  a  vivid  spark  is  produced.  .  .  .  The  effect 
appears  somewhat  increased  by  coiling  the  wire  into  a 
helix ;  it  seems  to  depend  in  some  measure  on  the  length 
and  thickness  of  the  wire ;  I  can  account  for  these  phe- 
nomena only  by  supposing  the  long  wire  to  become 
charged  with  electricity  which  by  its  reaction  on  itself 
projects  a  spark  when  the  connection  is  broken." 

Soon  after,  Henry  went  to  Princeton  and  there  con- 
tinued his  experiments  in  electromagnetism.  No  diffi- 
culty was  experienced  in  inducing  currents  of  the  third, 
fourth  and  fifth  orders  by  using  the  first  secondary  as 
primary  for  yet  another  secondary  circuit,  and  so  on 
(38,  209,  1840).  The  directions  of  these  currents  of 
higher  orders  when  the  primary  is  made  or  broken 
proved  puzzling  at  first,  but  were  satisfactorily  explained 
a  year  later  (41,  117,  1841).  In  addition  induced  cur- 
rents were  obtained  from  a  Leyden  jar  discharge.  Fara- 
day failed  to  find  any  screening  effect  of  a  conducting 
cylinder  placed  around  the  primary  and  inside  the 
secondary.  Henry  examined  the  matter,  and  found  that 
the  screening  effect  exists  only  when  the  induced  current 
is  due  to  a  make  or  break  of  the  primary  circuit,  and  not 
when  it  is  caused  by  motion  of  the  primary. 

Henry  ^s  work  was  mainly  descriptive ;  it  remained  for 
Faraday  to  develop  a  theory  to  account  for  the  phenomena 
discovered  and  to  prepare  the  way  for  quantitative  for- 
mulation of  the  laws  of  current  induction.  This  he  did  in 
his  representation  of  a  magnetic  field  by  means  of  lines 
of  force ;  a  conception  which  he  found  afterwards  to  be 
equally  valuable  when  applied  to  electrostatic  problems. 
Every  magnet  and  every  current  gives  rise  to  these 
closed  curves;  in  the  case  of  a  magnet  they  thread  it 
from  south  pole  to  north,  while  a  straight  wire  bearing 
a  current  is  surrounded  by  concentric  rings.  The  con- 
nection between  lines  of  force  and  the  induction  of  cur- 
rents is  contained  in  the  rule  that  a  current  is  induced  in 
a  closed  circuit  only  when  a  change  takes  place  in  the 
number  of  lines  of  force  passing  through  it.  Further- 
more the  dependence  of  the  current  strength  on  the 


A  CENTURY ^S  PROGRESS  IN  PHYSICS     343 

conductivity  of  the  wire  employed  has  led  to  recognition 
of  the  fact  that  it  is  the  electromotive  force  and  not  the 
current  itself  which  is  conditioned  by  the  change  in  mag- 
netic flux. 

Great  interest  was  attached  to  the  utilization  of  the 
newly  discovered  forces  of  electromagnetism.  In  1831 
Henry  (20,  340,  1831)  described  a  reciprocating  engine 
depending  on  magnetic  attraction  and  repulsion,  and  C. 
G.  Page  (33,  118,  1838;  49,  131,  1845)  devised  many 
others.  The  latter  ^s  most  important  work,  however,  was 
the  invention  of  the  Ruhmkorif  coil.  In  1836  (31,  137, 
1837)  he  found  the  strongest  shocks  to  be  obtained  from  a 
secondary  coil  of  many  windings  forming  a  continuation 
of  a  primary  of  half  the  number  of  turns.  His  perfec- 
tion of  the  self-acting  circuit  breaker  (35,  252,  1839) 
widened  the  usefulness  of  the  induction  coil,  and  his  sub- 
stitution of  a  bundle  of  iron  wires  for  a  solid  iron  core 
(34, 163, 1838)  greatly  increased  its  efficiency. 

Conservation  of  Energy. — Perhaps  the  most  important 
advance  of  the  nineteenth  century  has  been  the  estab- 
lishTnent  of  the  principle  of  conservation  of  energy. 
Despite  the  fact  that  the  *^principe  de  la  conservation  des 
force  vives''  had  been  recognized  by  the  French  mathe- 
maticians of  the  early  part  of  the  century,  the  application 
of  this  principle  even  to  purely  mechanical  problems  was 
contested  by  some  scientists.  Through  the  early  num- 
bers of  the  Journal  runs  a  lively  controversy  as  to 
whether  there  is  not  a  loss  of  power  involved  in  impart- 
ing momentum  to  the  reciprocating  parts  of  a  steam 
engine  only  to  check  the  motion  later  on  in  the  stroke. 
Finally  Isaac  Doolittle  (14,  60,  1828),  of  the  Bennington 
Iron  Works,  ends  the  discussion  by  the  pertinent  remark : 
**If  there  be,  as  is  contended  by  one  of  your  correspond- 
ents, a  loss  of  more  than  one  third  of  the  power,  in  trans- 
forniing  an  alternating  rectilinear  movement  into  a 
continuous  circular  one  by  means  of  a  crank,  I  should 
like  to  be  informed  what  would  be  the  effect  if  the  propo- 
sition were  reversed,  as  in  the  case  of  the  common 
saw  mill,  and  in  many  other  instances  in  practical 
mechanics. ' ' 

A  realization  of  the  equivalence  of  heat  and  mechani- 
cal work  did  not  come  until  the  middle  of  the  century,  in 


344  A  CENTURY  OF  SCIENCE 

spite  of  the  conclusive  experiments  of  the  American 
Count  Eumford  and  the  English  Davy  before  the  year 
1800.  So  firmly  enthroned  was  the  caloric  theory, 
according  to  which  heat  is  an  indestructible  fluid,  that 
evidence  against  it  was  given  scant  consideration.  In 
fact  the  success  of  the  analytical  method  introduced  by 
Fourier  in  1822  for  the  solution  of  problems  in  conduc- 
tion of  heat  only  added  to  the  difficulties  of  the  adherents 
of  the  kinetic  theory.  But  recognition  of  heat  as  a  form 
of  energy  was  on  the  way,  and  when  it  came  it  made  its 
appearance  almost  simultaneously  in  half  a  dozen  differ- 
ent places.  Perhaps  Robert  Mayer  of  Heilbronn  was 
the  first  to  state  explicitly  the  new  principle.  His  paper 
*^0n  the  Forces  of  Inorganic  Nature"  was  refused 
publication  in  Poggendorff 's  Annalen,  but  fared  better  at 
the  hands  of  another  editor.  During  the  next  few  years 
Joule  determined  the  mechanical  equivalent  of  heat 
experimentally  by  a  number  of  different  methods,  some 
of  which  had  already  been  devised  by  Carnot.  Of  those 
he  used,  the  most  familiar  consists  in  churning  up  a 
measured  mass  of  water  by  means  of  paddles  actuated  by 
falling  weights  and  calculating  the  heat  developed  from 
the  rise  in  temperature.  However,  the  work  of  the 
young  Manchester  brewer  received  little  attention  from 
the  members  of  the  British  Association  before  whom  it 
was  reported  until  Kelvin  showed  them  its  significance 
and  attracted  their  interest  to  it.  Meanwhile  Helmholtz 
had  completed  a  very  thorough  disquisition  on  the  con- 
servation of  energy  not  only  in  dynamics  and  heat  but  in 
other  departments  of  physics  as  well.  His  paper  on 
''Die  Erhaltung  der  Kraft''  was  frowned  upon  by  the 
members  of  the  Physical  Society  of  Berlin  before  whom 
he  read  it,  and  received  the  same  treatment  as  Mayer's 
from  the  editor  of  Poggendorff's  Annalen.  Helmholtz 's 
*' Kraft,"  like  the  ''vis  viva"  of  other  writers,  is  the 
quantity  which  Young  had  already  christened  energy. 
Not  many  years  elapsed,  however,  until  the  convictions  of 
Mayer,  Joule,  Kelvin  and  Helmholtz  became  the  most 
clearly  recognized  of  all  physical  principles.  As  early 
as  1850  Jeremiah  Day  (10,  174,  1850),  late  president  of 
Yale  College,  admitted  the  improbability  of  constructing 


A  CENTURY'S  PROGRESS  IN  PHYSICS     346 

a  machine  capable  of  perpetual  motion,  even  though  the 
** imponderable  agents''  of  electricity,  galvanism  and 
magnetism  be  utilized. 

Thermodynamics. — The  importance  of  the  principle  of 
conservation  of  energy  lies  in  the  fact  that  it  unites  under 
one  rule  such  diverse  phenomena  as  gravitation,  electro- 
magnetism,  heat  and  chemical  action.  Another  principle 
as  universal  in  its  scope,  although  depending  upon  the 
coarseness  of  human  observations  for  its  validity  rather 
than  upon  the  immutable  laws  of  nature,  was  fore- 
shadowed even  before  the  first  law  of  thermodynamics, 
or  principle  of  conservation  of  energy,  was  clearly 
recognized.  This  second  law  was  the  consequence  of 
efforts  to  improve  the  efficiency  of  heat  engines.  In  1824 
Carnot  introduced  the  conception  of  cyclic  operations 
into  the  theory  of  such  engines.  Assuming  the  impos- 
sibility of  perpetual  motion,  he  showed  that  no  engine  can 
have  an  efficiency  greater  than  that  of  a  reversible 
engine.  Finally  Clausius  expressed  concisely  the  princi- 
ple toward  which  Carnot 's  work  had  been  leading,  when 
he  asserted  that  *4t  is  impossible  for  a  self-acting 
machine,  unaided  by  any  external  agency,  to  convey  heat 
from  one  body  to  another  at  a  higher  temperature." 
Kelvin's  formulation  of  the  same  law  states  that  **it  is 
impossible,  by  means  of  inanimate  material  agency,  to 
derive  mechanical  effect  from  any  portion  of  matter  by 
cooling  it  below  the  temperature  of  the  coldest  of  the 
surrounding  objects. ' ' 

The  consequences  of  the  second  law  were  rapidly 
developed  by  Kelvin,  Clausius,  Rankine,  Barnard  (16, 
218,  1853,  et  seq.)  and  others.  Kelvin  introduced  the 
thermodynamic  scale  of  temperature,  which  he  showed 
to  be  independent  of  such  properties  of  matter  as  con- 
dition the  size  of  the  degree  indicated  by  the  mercury 
thermometer.  This  scale,  which  is  equivalent  to  that  of 
the  ideal  gas  thermometer,  was  used  subsequently  by 
Rowland  in  his  exhaustive  determination  of  the  mechan- 
ical equivalent  of  heat  by  an  improved  form  of  Joule's 
method.  He  found  different  values  for  different  ranges 
in  temperature,  showing  that  the  specific  heat  of  water 
is  by  no  means  constant.     Since  then  electrical  methods 


346  A  CENTURY  OF  SCIENCE 

of  measuring  this  important  quantity  have  been  used  to 
confirm  the  results  of  purely  mechanical  determinations. 

The  definition  of  a  new  quantity,  entropy,  was  found 
necessary  for  a  mathematical  formulation  of  the  second 
law  of  thermodynamics.  This  quantity,  which  acts  as  a 
measure  of  the  unavailability  of  heat  energy,  was  given 
a  new  significance  when  Boltzmann  showed  its  connec- 
tion with  the  probability  of  the  thermodynamic  state  of 
the  substance  under  consideration.  If  two  bodies  have 
widely  different  temperatures,  a  large  amount  of  the 
heat  energy  of  the  system  is  available  for  conversion 
into  mechanical  work.  From  the  macroscopic  point  of 
view  this  is  expressed  by  saying  that  the  entropy  is  small, 
or  if  the  motions  of  the  individual  molecules  are  taken 
into  account,  the  probability  of  the  state  is  low.  The 
interpretation  of  entropy  as  the  logarithm  of  the  thermo- 
dynamic probability  has  thrown  much  light  on  the 
meaning  of  this  rather  abstruse  quantity.  Gibbs's 
**  Elementary  Principles  in  Statistical  Mechanics '*  treats 
in  detail  the  fundamental  assumptions  involved  in 
this  point  of  view,  its  limitations  and  its  consequences. 
In  his  * ^ Equilibrium  of  Heterogeneous  Substances'^^ 
he  had  already  extended  the  principle  of  thermal  equi- 
librium to  include  substances  which  are  no  longer  homo- 
geneous. The  value  of  the  chemical  potential  he  intro- 
duced determines  whether  one  phase  is  to  gain  at  the 
expense  of  another  or  lose  to  it.  It  is  unfortunate  that 
the  analytical  rigor  and  austerity  of  his  reasoning  com- 
bined with  lack  of  mathematical  training  on  the  part  of 
the  average  chemist,  delayed  true  appreciation  of  his 
work  and  full  utilization  of  the  new  field  which  he 
opened  up. 

Liquefaction  of  Gases. — ^Meanwhile  the  problem  of 
liquefying  gases  was  attracting  much  attention  on  the 
part  of  experimental  physicists.  Faraday  had  succeeded 
in  making  liquid  a  number  of  substances  which  had 
hitherto  been  known  only  in  the  gaseous  state.  His 
method  consists  in  evolving  the  gas  from  chemicals 
placed  in  one  end  of  a  bent  tube,  the  other  end  of  which 
is  immersed  in  a  freezing  mixture.  The  high  pressure 
caused  by  the  production  of  the  gas  combined  with  the 
low  temperature  is  sufficient  to  bring  about  liquefaction 


A  CENTURY'S  PROGRESS  IN  PHYSICS     347 

in  many  cases.  Failure  with  other  more  permanent 
gases  was  unexplained  until  the  researches  of  Andrews 
in  1863  showed  that  no  amount  of  pressure  will  produce 
liquefaction  unless  the  temperature  is  below  a  certain 
critical  value.  The  method  of  reducing  the  temperature 
in  use  to-day  depends  on  a  fact  discovered  by  Kelvin  and 
Joule  in  connection  with  the  free  expansion  of  a  gas. 
These  investigators  allowed  the  gas  to  escape  through  a 
porous  plug  from  a  chamber  in  which  the  pressure  was 
relatively  high.  With  the  single  exception  of  hydrogen, 
the  effect  of  the  sudden  expansion  is  to  cool  the  gas,  and 
even  with  it  cooling  is  found  to  take  place  after  the  tem- 
perature has  been  made  sufficiently  low.  By  this  method 
all  known  gases  have  been  liquefied.  Helium,  with  a 
boiling  point  of  — 269° C,  or  only  4°C.  above  the  absolute 
zero,  was  the  last  to  be  made  a  liquid,  finally  yielding  to 
the  efforts  of  Kammerlingh  Onnes  in  1907.  This  inves- 
tigator^  finds  that  at  temperatures  near  the  absolute  zero 
the  electrical  conductivity  of  certain  substances  undergoes 
a  profound  modification.  For  example,  a  coil  of  lead 
shows  a  superconductivity  so  great  that  a  current  once 
started  in  it  persists  for  days  after  the  electromotive 
force  has  ceased  to  act. 

Electrodynamics. — Faraday's  representation  of  elec- 
tric and  magnetic  fields  by  lines  of  force  had  been  of 
great  value  in  predicting  the  results  of  experiments  in 
electromagnetism.  But  a  more  mathematical  formula- 
tion of  the  laws  governing  these  phenomena  was  needed 
in  order  to  make  possible  quantitative  development  of 
the  theory.  This  was  supplied  by  Maxwell  in  his 
epoch-making  treatise  on  **  Electricity  and  Mag- 
netism." Starting  with  electrostatics  and  magnetism, 
he  gives  a  complete  account  of  the  mathematical 
methods  which  had  been  devised  for  the  solution 
of  problems  in  these  branches  of  the  subject,  and 
then  turning  to  Ampere's  work  he  shows  how  the 
Lagrangian  equations  of  motion  lead  to  Faraday's  law 
if  the  single  assumption  is  made  that  the  magnetic 
energy  of  the  field  is  kinetic.  In  the  treatment  of  open 
circuits  Maxwell's  intuition  led  to  a  great  advance,  the 
introduction  of  the  displacement  current.  Consider  a 
charged  condenser,  the  plates  of  which  are  suddenly  con- 


348  A  CENTURY  OF  SCIENCE 

nected  by  a  wire.  A  current  will  flow  through  the  wire 
from  the  positively  charged  plate  to  the  negative,  but  in 
the  gap  between  the  two  plates  the  conduction  current 
is  missing.  So  convinced  was  Maxwell  that  currents 
must  always  flow  in  closed  circuits,  that  he  postulated  an 
electrical  displacement  in  the  medium  between  the  plates 
of  a  charged  condenser,  which  disappears  when  the  con- 
denser is  short-circuited.  Thus  even  in  the  so-called 
open  circuit  the  current  flows  along  a  closed  path. 

Maxwell's  theory  of  the  electromagnetic  field  is  based 
essentially  on  Faraday's  representation  by  lines  of  force 
of  the  strains  and  stresses  of  a  universal  medium.  So  it 
is  not  surprising  that  he  was  led  to  a  consideration  of 
the  propagation  of  waves  through  this  medium.  The 
introduction  of  the  displacement  current  made  the  form 
of  the  electrodynamic  equations  such  as  to  yield  a  typical 
wave  equation  for  space  free  from  electrical  charges  and 
currents.  Moreover,  the  disturbance  was  found  to  be 
transverse,  and  its  velocity  turned  out  to  be  identical 
with  that  of  light.  The  conclusion  was  irresistible. 
That  light  could  consist  of  anything  but  electromagnetic 
waves  of  extremely  short  length  was  inconceivable.  In 
fact  so  certain  was  Maxwell  of  this  deduction  from 
theory  that  he  felt  it  altogether  unnecessary  to  resort  to 
the  test  of  experiment.  For  the  electromagnetic  theory 
explained  so  many  of  the  details  which  had  been  revealed 
by  experiments  in  light,  that  no  doubt  of  its  validity 
could  be  entertained.  Even  dispersion  received  ready 
elucidation  on  the  assumption  that  the  dispersing 
medium  is  made  up  of  vibrators  having  a  natural  period 
comparable  with  that  of  the  light  passing  through  it. 

Maxwell's  book  was  published  in  1873.  Fifteen  years 
later,  Hertz,^  at  the  instigation  of  Helmholtz,  succeeded 
in  detecting  experimentally  the  electromagnetic  waves 
predicted  by  Maxwell's  theory.  His  oscillator  consisted 
of  two  sheets  of  metal  in  the  same  plane,  to  each  of  which 
was  attached  a  short  wire  terminating  in  a  knob.  The 
knobs  were  placed  within  a  short  distance  of  each  other, 
and  connected  to  the  terminals  of  an  induction  coil.  By 
reflection  standing  waves  were  formed,  and  the  positions 
of  nodes  and  loops  determined  by  a  detector  composed  of 
a  movable  loop  of  wire  containing  an  air  gap.     Thus  the 


■^.:-^ 


-^m^ 


A  CENTURY'S  PROGRESS  IN  PHYSICS     349 

wave  length  was  measured.  Hertz  calculated  the  fre- 
quency of  his  radiator  from  its  dimensions,  and  then 
computed  the  velocity  of  the  disturbance.  In  spite  of  an 
error  in  his  calculations,  later  pointed  out  by  Poincare, 
he  obtained  very  nearly  the  velocity  of  light  for  waves 
traveling  through  air,  but  a  velocity  considerably  smaller 
for  those  propagated  along  wires.  Subsequent  work  by 
Lecher,  Sarasin  and  de  la  Rive,  and  Trowbridge  and 
Duane  (49,  297,  1895;  50,  104,  1895)  cleared  up  this  dis- 
crepancy, and  showed  the  velocity  to  be  in  both  cases 
identical  with  that  of  light.  The  last-named  investiga- 
tors increased  the  size  of  the  oscillator  until  it  was  possi- 
ble to  measure  the  frequency  by  photographing  the  spark 
in  the  secondary  with  a  rotating  mirror.  The  positions 
of  nodes  and  loops  were  obtained  by  means  of  a  bolom- 
eter after  the  secondary  had  been  tuned  to  resonance 
with  the  vibrator.  The  velocity  thus  found  for  electro- 
magnetic waves  along  wires  is  within  one-tenth  of  one 
percent  of  the  accepted  value  of  the  velocity  of  light. 
Hertz's  later  experiments  showed  that  waves  in  air  suf- 
fer refraction  and  diffraction,  and  he  succeeded  in 
polarizing  the  radiation  by  passing  it  through  a  grating 
constructed  of  parallel  metallic  wires.  » 

In  order  to  satisfy  the  law  of  action  and  reaction,  it 
is  found  necessary  to  attribute  a  quasi-momentum  to 
electromagnetic  waves.  When  a  train  of  such  waves  is 
absorbed,  their  momentum  is  transferred  to  the  absorb- 
ing body,  while  if  they  are  reflected  an  impulse  twice  as 
great  is  imparted.  This  consequence  of  theory,  foreseen 
by  Maxwell  and  developed  in  detail  by  Poynting,  Abra- 
ham and  Larmor,  has  been  verified  by  the  experiments  of 
Lebedew,  and  Nichols  and  Hull.*  The  latter  used  a  deli- 
cate torsion  balance  from  which  was  suspended  a  couple 
of  silvered  glass  vanes.  In  order  to  eliminate  the  effect 
of  impulses  imparted  by  the  molecules  of  the  residual 
gas,  such  as  Crookes  had  observed  in  his  radiometer, 
readings  were  made  at  many  different  pressures  and  the 
ballistic  rather  than  the  static  deflection  recorded. 
After  the  pressure  produced  by  light  from  a  carbon  arc 
had  been  measured,  the  intensity  of  the  radiation  was 
determined  with  a  bolometer.  Preliminary  experiments 
indicated   the    existence    of   a   pressure    of   the    order 


350  A  CENTURY  OF  SCIENCE 

expected,  and  later  more  careful  measurements  showed 
good  quantitative  agreement  with  theory.  This  pressure 
had  already  found  an  important  application  in  Lebedew's 
explanation  of  the  solar  repulsion  of  comet's  tails. 
These  tails  are  made  up  of  enormous  swarms  of  very 
minute  particles,  and  as  the  comet  swings  around  the 
sun  they  suffer  a  repulsion  due  to  the  pressure  of  the 
intense  solar  radiation  which  counteracts  the  sun's  gravi- 
tational attraction.  Hence  the  tail,  instead  of  following 
after  the  comet  in  its  orbit,  points  in  a  direction  away 
from  the  sun. 

Some  uncertainty  existed  as  to  whether  a  convection 
current  produces  a  magnetic  field.  A  compass  needle 
is  deflected  by  a  current  from  a  Daniell  cell ;  is  the  same 
effect  obtained  when  a  conductor  is  charged  electro- 
statically and  then  whirled  around  the  needle  by  means 
of  an  insulating  handle?  The  experimental  difficulties 
involved  in  settling  this  question  are  realized  when  the 
enormous  difference  between  the  electrostatic  and  elec- 
tromagnetic units  of  current  is  taken  into  consideration. 
For  a  sphere  one  centimeter  in  radius,  charged  to  a 
potential  of  20,000  volts,  and  revolving  in  a  circle  sixty 
times  a  second,  constitutes  a  current  of  little  over  a 
millionth  of  an  ampere. 

This  problem  was  undertaken  by  Rowland  (15,  30, 
1878)  in  Helmholtz's  laboratory  at  Berlin  in  1876.  A 
hard  rubber  disk  coated  on  both  sides  with  gold  was 
charged  and  rotated  about  a  vertical  axis  at  a  rate  of 
sixty  revolutions  a  second.  On  reversing  the  sign  of  the 
electrification  on  the  disk,  the  astatic  needle  hung  above 
its  center  showed  a  deflection  of  over  five  millimeters. 
The  current  was  calculated  in  electrostatic  units  from  the 
charge  on  the  disk  and  its  rate  of  motion,  and  in  electro- 
magnetic units  from  the  magnetic  deflection.  The  ratio 
of  these  two  quantities  gave  fair  agreement  with  its  theo- 
retical value,  the  velocity  of  light. 

Although  the  result  of  this  experiment  was  confirmed 
by  Rowland  and  Hutchinson  in  1889,  Cremieu  was  con- 
vinced by  an  investigation  carried  out  at  Paris  in  1900 
that  the  Rowland  effect  did  not  exist.  Consequently 
further  repetition  of  the  experiment  was  desirable.  So 
the  following  year  Adams  (12,  155,  1901)  arranged  two 


A  CENTURY'S  PROGRESS  IN  PHYSICS     351 

rings  of  eight  spheres  each  so  that  they  could  be  rotated 
about  their  common  axis  from  fifty  to  sixty  times  a  sec- 
ond. One  set  of  spheres  was  connected  by  brushes  to  the 
positive  pole  of  a  battery  of  20,000  volts,  the  other  to  the 
negative  pole.  The  deflection  of  a  nearby  magnetometer 
needle  was  observed  when  the  electrification  of  the  two 
rings  was  reversed,  and  from  the  reading  so  obtained  the 
ratio  of  the  electromagnetic  to  the  electrostatic  unit  of 
current  computed.  This  quantity  was  found  to  differ 
from  the  velocity  of  light  by  only  a  few  percent.  This 
experiment  and  the  even  more  exhaustive  investigations 
carried  out  by  Pender,  both  independently  and  in  collab- 
oration with  Cremieu,  finally  convinced  the  scientific 
world  that  a  convection  current  produces  the  same  mag- 
netic field  as  a  conduction  current  of  the  same  magnitude. 

In  discussing  the  ponderomotive  force  experienced  in  a 
magnetic  field  by  a  conductor  through  which  a  current  is 
passing,  Maxwell  had  said,  ^^It  must  be  carefully  remem- 
bered, that  the  mechanical  force  which  urges  a  conductor 
carrying  a  current  across  the  lines  of  magnetic  force, 
acts,  not  on  the  electric  current,  but  on  the  conductor 
which  carries  it."  Hall  (19,  200,  1880),  one  of  Row- 
land's students,  questioned  this  statement,  and  deter- 
mined to  put  it  to  the  test  of  experiment.  Efforts  to  find 
an  increase  in  the  resistance  of  a  wire  placed  at  right 
angles  to  the  lines  of  magnetic  force  were  unsuccessful. 
So  the  current  was  passed  through  a  moderately  broad 
strip  of  gold  leaf  and  the  effect  of  the  magnetic  field 
on  the  equipotential  lines  investigated.  The  results 
obtained  confirmed  HalPs  belief  that  the  force  exerted  by 
the  field  acts  on  the  current  itself,  and  is  transmitted 
through  it  to  the  conductor.  Further  investigation  (20, 
161,  1880)  revealed  the  same  deflection  of  equipotential 
lines  in  thin  strips  of  other  metals,  although  the  effect 
was  found  to  be  reversed  in  iron. 

During  the  closing  years  of  the  nineteenth  century 
occurred  three  events  of  far  reaching  importance.  The 
electron  was  isolated,  and  its  charge  and  mass  measured 
by  J.  J.  Thomson  in  England;  X-rays  were  discovered 
by  Rontgen  in  Germany;  and  the  first  indications  of 
radioactivity  were  found  by  Becquerel  in  France.  The 
first  two  are  certainly  to  be  attributed  largely  to  the 


352  A  CENTURY  OF  SCIENCE 

great  advances  which  had  been  .made  in  obtaining  high 
vacua,  and  the  last  two  might  not  have  occurred  so  soon 
had  it  not  been  for  the  photographic  plate. 

The  Electron. — The  atomic  theory  of  electricity  dates 
from  the  time  of  Faraday.  His  experiments  on  electroly- 
sis showed  that  each  monovalent  atom  or  radical,  what- 
ever its  nature,  carries  the  same  charge,  each  bivalent  ion 
a  charge  twice  as  great.  Only  a  lack  of  knowledge  of  the 
number  of  atoms  in  a  gram  of  the  dissociated  salt  pre- 
vented him  from  calculating  the  value  of  the  elementary 
charge.  As  the  discharge  of  electricity  through  gases  at 
low  pressures  became  a  subject  for  experimental  inves- 
tigation, another  line  of  approach  to  the  study  of  the 
atom  of  electricity  was  opened  up.  As  early  as  the  sev- 
enties Hittorf  and  Goldstein  had  observed  that  a  shadow 
is  cast  by  a  screen  placed  in  front  of  the  cathode  of  a 
Crookes  tube.  Varley  suggested  that  the  cathode  rays 
producing  the  shadow  consist  of  ^  *  attenuated  particles  of 
matter,  projected  from  the  negative  pole  by  electricity.'' 
The  discovery  that  these  rays  are  deflected  by  a  magnetic 
field  led  English  physicists  to  the  conclusion  that  they 
must  be  composed  of  charged  particles,  and  the  direction 
of  the  deflection  was  such  as  to  require  the  charge  to  be 
negative.  Hertz  contested  this  view  on  the  ground  that 
his  experiments  showed  the  rays  to  be  unaffected  by  an 
electrostatic  field,  and  suggested  that  they  consist  of 
etherial  disturbances.  Finally  Perrin  succeeded  in  pass- 
ing the  rays  into  a  metal  cylinder  which  received  from 
them  a  negative  charge,  and  Lenard  showed  how  exces- 
sively minute  these  negatively  charged  particles  must  be 
by  actually  passing  them  through  a  thin  sheet  of  alumi- 
nium in  the  wall  of  a  vacuum  tube,  and  detecting  their 
presence  in  the  air  outside.  Conclusive  information  as 
to  the  nature  of  the  electron,  as  it  was  named  by  John- 
stone Stoney,  was  supplied  by  the  classic  experiments 
of  J.  J.  Thomson.^  First  he  showed  that  Hertz's  failure 
to  find  a  deflection  when  a  stream  of  electrons  passes 
between  the  plates  of  a  charged  condenser  was  due  to  the 
screening  effect  of  the  gaseous  ions  produced  by  the  dis- 
charge. With  a  much  more  highly  evacuated  tube  he 
found  no  difficulty  in  obtaining  a  deflection  in  an  electro- 
static field.    By  using  crossed   electric   and  magnetic 


A  CENTURY'S  PROGRESS  IN  PHYSICS     363 

fields  the  deflection  produced  by  one  was  just  balanced  by 
that  caused  by  the  other,  and  from  the  field  strengths 
employed  both  the  velocity  of  the  particles  and  the  ratio 

—  of  charge  to  mass  was  calculated.    The  former  was 

found  to  be  about  one-tenth  the  velocity  of  light,  but  the 
most  startling  result  of  the  experiment  was  that  the  same 

value  of  -—  was  obtained  no  matter  what  residual  gas 

in 

was  contained  in  the  tube  or  of  what  metal  the  cathode 
was  made. 

To  calculate  e  and  then  m  other  methods  are  necessary. 
C.  T.  R.  Wilson  has  shown  that  in  supersaturated  air, 
water  drops  form  easily  on  charged  molecules,  and  that 
negative  ions  are  more  effective  in  causing  condensation 
than  positive  ones.  By  making  use  of  the  results  of  this 
research  Thomson  has  been  able  to  measure  the  elemen- 
tary charge.  For  suppose  a  stream  of  negative  ions  to 
pass  through  supersaturated  air.  A  little  drop  forms 
on  each  charged  particle,  and  the  cloud  of  condensed 
vapor  settles  to  the  bottom  of  the  vessel.  The  charge 
carried  and  the  mass  of  water  deposited  can  be  meas- 
ured directly.  Stokes'  law  for  the  rate  of  fall  of  a 
minute  particle  through  a  gaseous  medium  enables  the 
average  size  of  the  drops  to  be  computed  from  the 
observed  rate  of  descent  of  the  cloud.  Hence  the  number 
of  drops  formed  and  the  charge  carried  by  each  follows 
at  once.  H.  A.  Wilson  improved  the  method  by  noting 
the  effect  of  an  electric  field  upon  the  rate  of  fall  of  the 
charged  drops,  and  subsequent  experiments  undertaken 
by  Millikan^  have  been  of  such  a  character  as  to  enable 
him  to  follow  the  motion  of  a  single  drop.  Instead  of 
water,  the  latter  uses  oil  drops  less  than  one  ten- 
thousandth  of  a  centimeter  in  diameter.  A  drop,  after 
one  or  more  electrons  have  attached  themselves  to  it, 
is  actually  weighed  in  terms  of  the  charge  on  its  surface 
by  applying  an  upward  electric  force  just  sufficient  to 
balance  the  force  of  gravity.  Then  its  weight  is  inde- 
pendently obtained  from  the  density  of  the  oil  and  the 
radius  of  the  drop  as  determined  by  the  rate  of  fall  when 
the  electric  field  is  absent.  Comparison  of  these  two 
expressions  gives  4-774(10)-^^  electrostatic  units  for  the 


364  A  CENTURY  OF  SCIENCE 

elementary    charge.     Combining    this    result   with    the 

value  of  —  found  by  Thomson,  the  mass  of  the  electron 

comes  out  to  be  about  one  eighteen-hundredth  that  of  an 
atom  of  the  lightest  known  element,  hydrogen. 

That  the  electron  is  a  fundamental  constituent  of  all 
matter  is  attested  by  the  fact  that  charge  and  mass  are 
the  same  regardless  of  the  source  or  manner  of  produc- 
tion. Whether  emitted  by  a  heated  metal,  under  the 
action  of  ultra-violet  light,  from  a  radioactive  substance, 
by  a  body  exposed  to  X-rays,  as  a  result  of  friction,  it  is 
the  same  negatively  charged  particle  that  constitutes  the 
cathode  ray  of  the  discharge  tube.  Moreover,  it  makes 
its  effect  felt  indirectly  in  many  other  phenomena,  and 
from  an  investigation  of  some  of  these  the  ratio  of 
charge  to  mass  can  be  determined  independently.  Of 
such  perhaps  the  most  interesting  is  the  Zeeman  effect. 

Spectroscopy. — Early  in  the  nineteenth  century  Fraun- 
hofer  had  observed  that  the  solar  spectrum  is  crossed 
by  a  large  number  of  dark  lines.  Their  presence  was 
unexplained  until  in  1859  Kirchhoff  and  Bunsen  showed 
**that  a  colored  flame,  the  spectrum  of  which  contains 
bright  sharp  lines,  so  weakens  rays  of  the  color  of  these 
lines  when  they  pass  through  it,  that  dark  lines  appear 
in  place  of  bright  lines  as  soon  as  there  is  placed  behind 
the  flame  a  light  of  sufficient  intensity,  in  which  the  lines 
are  otherwise  absent.''  For  intra-atomic  oscillators 
must  have  the  natural  frequency  of  the  radiation  which 
they  emit,  and  consequently  resonance  will  take  place 
when  they  are  exposed  to  rays  of  this  frequency  coming 
from  an  outside  source,  and  selective  absorption  ensue. 
By  comparing  the  bright  lines  in  the  spectra  of  metallic 
vapors  made  luminous  by  a  gas  flame  with  the  dark  lines 
in  the  sun's  spectrum  these  investigators  showed  that 
many  of  the  common  terrestrial  elements  exist  in  the 
sun.  The  interest  in  spectroscopy  grew  rapidly.  The 
excellent  diffraction  gratings  made  by  Rutherfurd  were 
succeeded  by  the  superior  concave  gratings  of  Rowland. 
In  1877  Draper  (14,  89,  1877)  announced  the  discovery  of 
the  bright  lines  of  oxygen  in  the  solar  spectrum,  but  his 
interpretation  of  his  photographs  has  not  been  corrob- 
orated by  the  work  of  later  investigators.    Langley  (11, 


A  CENTURY'S  PROGRESS  IN  PHYSICS     355 

401,  1901),  by  the  aid  of  his  newly  invented  bolometer, 
succeeded  in  detecting  the  emission  of  energy  from  the 
sun  in  the  infra-red  in  amounts  far  exceeding  that  con- 
tained in  the  visible  spectrum.  In  1842  Doppler  drew 
attention  to  the  fact  that  motion  of  the  source  should 
cause  a  displacement  of  the  spectral  lines,  the  shift  being 
to  the  blue  if  the  light  is  approaching  and  to  the  red  if 
it  is  receding,  and  a  few  years  later  Fizeau  suggested  the 
application  of  Doppler 's  principle  to  the  measurement  of 
the  velocity  of  a  star  moving  in  the  line  of  sight.  Thus 
the  spectroscope  has  been  able  to  supply  one  of  the 
deficiencies  of  the  telescope,  and  the  two  together  are 
sufficient  to  reveal  all  components  of  stellar  motion. 
When  spectra  formed  by  light  from  the  sun's  limb  and 
from  its  center  are  compared,  the  same  effect  reveals 
the  rotation  of  the  sun  about  its  axis.  (C.  S.  Hastings,  5, 
369,  1873;  C.  A.  Young,  12,  321,  1876.) 

Further  Evidence  of  the  Electron. — In  1845  Faraday 
discovered  a  rotation  of  the  plane  of  polarization  when 
light  passes  in  the  direction  of  the  lines  of  force  through 
a  piece  of  glass  placed  between  the  poles  of  an  electro- 
magnet. Examination  of  the  spectrum  from  a  glowing 
vapor  situated  between  the  poles  of  a  magnet,  however, 
failed  to  reveal  any  effect  of  the  field.  The  latter  prob- 
lem was  attacked  anew  by  Zeeman^  in  1896,  and  with  the 
aid  of  the  improved  appliances  of  modern  science  he  suc- 
ceeded in  detecting  a  broadening  of  the  lines.  Later 
experiments  with  more  powerful  apparatus  resolved 
these  broadening  lines  into  several  components. 

Lorentz^  showed  at  once  how  the  electron  theory  fur- 
nishes an  explanation  of  the  Zeeman  effect.  He  found 
that  when  the  source  is  viewed  at  right  angles  to  the  lines 
of  magnetic  force,  a  spectral  line  should  be  split  into 
three  components.  Of  these  he  predicted  that  the  mid- 
dle, or  undisplaced  component,  would  be  found  to  be 
polarized  at  right  angles  to  the  direction  of  the  field,  and 
the  other  components  parallel  to  the  field.  When  the 
light  proceeds  from  the  source  in  a  direction  parallel  to 
the  magnetic  lines  of  force,  two  components  only  should 
be  formed,  and  these  should  be  circularly  polarized  in 
opposite  senses.  Moreover,  from  the  separation  of  the 
components  can  be  calculated  the  ratio  of  charge  to  mass 


856  A  CENTURY  OF  SCIENCE 

of  the  electronic  vibrator  which  is  responsible  for  the 
emission  of  radiant  energy.  Zeeman's  experiments  con- 
firmed Lorentz's  theory  in  every  detail,  and  yielded  a 

value  of  —  in  substantial  agreement  with  that  obtained 

for  cathode  rays.  Subsequent  research,  however,  has 
shown  that  in  many  cases  more  components  are  found 
than  the  elementary  theory  calls  for.  Hale  has  detected 
the  Zeeman  effect  in  light  from  sun  spots,  proving  that 
these  blemishes  on  the  sun's  face  are  vortices  caused  by 
whirling  swarms  of  electrified  particles.  Recently  Stark 
and  Lo  Surdo  have  found  a  similar  splitting  up  of  lines 
in  the  spectrum  formed  by  light  from  canal  rays  (rays  of 
positively  charged  particles)  passing  through  an  intense 
electric  field.  This  phenomenon  has  as  yet  received  no 
adequate  explanation. 

On  discovering  that  an  electric  current  is  capable  of 
producing  a  magnetic  field,  Ampere  had  suggested  that 
the  magnetic  properties  of  such  substances  as  iron  might 
be  explained  on  the  assumption  of  molecular  currents. 
The  electron  theory  considers  these  currents  to  be  due  to 
the  revolution,  inside  the  atom,  of  negatively  charged 
particles  about  an  attracting  nucleus.  It  occurred  to 
Richardson  that  this  motion  should  give  the  atom  the 
properties  of  a  gyrostat.  Hence  if  an  iron  bar  be  rotated 
about  its  axis,  the  atoms  should  orient  themselves  so  as  to 
make  their  axes  more  nearly  parallel  to  the  axis  of  rota- 
tion. Thus  its  rotation  should  cause  the  bar  to  become 
a  magnet.  Barnett^  has  tested  this  hypothesis,  and  has 
found  the  effect  Richardson  had  predicted.     From  the 

strength  of  the  magnetization  produced,  the  value  of  — 

can  be  computed.  Barnett  finds  a  value  somewhat 
smaller  than  that  for  cathode  rays,  but  of  the  right  order 
of  magnitude  and  sign.  Einstein  and  De  Haas  have 
detected  the  inverse  of  this  effect,  i.  e.,  the  rotation  of  an 
iron  rod  when  it  is  suddenly  magnetized. 

X-Rays. — In  1895,  on  developing  a  plate  which  had 
been  lying  near  a  vacuum  tube,  Rontgen^^  was  surprised 
to  find  distinct  markings  on  it.  As  the  plate  had  never 
been  exposed  to  light,  it  was  necessary  to  suppose  the 


A  CENTURY'S  PROGRESS  IN  PHYSICS    357 

effect  to  be  due  to  some  new  and  unknown  type  of  radia- 
tion. Further  investigation  showed  that  this  radiation 
originates  at  the  points  where  cathode  rays  impinge  on 
the  glass  walls  of  the  tube.  Besides  being  able  to  pass 
with  ease  through  all  but  the  most  dense  material  objects 
X-rays  were  found  to  have  the  power  of  ionizing  gases 
through  which  they  pass  and  ejecting  electrons  from  metal 
surfaces  against  which  they  strike.  The  points  at  which 
these  electrons  are  produced  are  in  turn  the  sources  of 
secondary  X-rays  whose  properties  are  characteristic  of 
the  metal  from  which  they  come. 

Rontgen's  discovery  excited  intense  interest  among 
laymen  as  well  as  in  scientific  circles.  Of  the  many 
X-ray  photographs  taken,  those  of  Wright  (1,  235,  1896) 
of  Yale  were  the  first  to  be  produced  in  this  country. 
His  experiments  were  made  immediately  on  receipt  of 
the  news  of  Rontgen's  research,  and  resulted  in  the  pub- 
lication of  a  number  of  photographs  showing  the  trans- 
lucency  for  these  rays  of  paper,  wood,  and  even 
aluminium. 

As  X-rays  are  undeviated  by  electric  or  magnetic  fields, 
Schuster,  and  later  Wiechert  and  Stokes,  suggested  that 
they  might  be  electromagnetic  waves  of  the  same  nature 
as  light,  but  much  shorter  and  less  regular.  The  great 
objection  to  this  hypothesis  was  the  failure  either  to 
refract  or  diffract  these  rays.  In  fact  Bragg  contended 
that  they  were  not  etherial  disturbances  at  all,  but  con- 
sisted of  neutral  particles  moving  with  very  high  veloci- 
ties. Finally  Laue^^  demonstrated  their  undulatory 
nature  by  showing  that  diffraction  took  place  under 
proper  conditions.  Just  as  the  distance  between  adja- 
cent lines  of  a  grating  must  be  comparable  to  the  wave 
length  of  light  for  a  spectrum  to  be  formed,  a  periodic 
structure  with  a  grating  space  of  their  very  much  shorter 
wave  length  is  necessary  to  diffract  X-rays.  Such  a 
structure  is  altogether  too  fine  to  be  made  by  human 
tools.  Nature,  however,  has  already  prepared  it  for 
man's  use.  The  distance  between  the  atoms  of  a  crystal 
is  just  right  to  make  it  an  excellent  X-ray  grating,  and 
Laue  had  no  difficulty  in  obtaining  diffraction  patterns 
when  Rontgen  rays  were  passed  through  a  block  of  zinc- 
blende.     The  distance  between  adjacent  atoms  of  this 


358  A  CENTURY  OF  SCIENCE 

cubic  crystal  can  be  computed  at  once  from  its  density 
and  molecular  weight,  and  then  the  wave  length  of  the 
radiation  calculated  from  the  deviation  suffered.  In  this 
way  X-rays  are  found  to  have  a  length  less  than  one 
thousandth  as  great  as  visible  light.  Further  study  of 
this  phenomenon,  particularly  by  the  two  Braggs,  father 
and  son,  has  revealed  many  of  the  structural  details  of 
more  complicated  crystals. 

The  most  significant  investigation  in  the  field  opened 
up  by  Lane's  discovery  is  that  undertaken  by  Moseley^^ 
only  a  couple  of  years  before  he  lost  his  life  in  the 
trenches  at  Gallipoli.  Using  many  different  metals  as 
anticathodes  in  a  vacuum  tube,  he  measured  the  fre- 
quencies of  the  characteristic  rays  emitted.  He  found 
that  if  the  elements  are  arranged  in  order  of  increasing 
atomic  weight,  the  square  roots  of  the  characteristic  fre- 
quencies form  an  arithmetical  progression.  If  to  each 
element  is  assigned  an  integer,  beginning  with  one  for 
hydrogen,  two  for  helium,  and  so  on,  the  square  root  of 
the  frequency  of  the  characteristic  radiation  is  found  to 
be  proportional  to  this  atomic  number.  Even  though 
Uhler  has  shown  recently  that  over  wide  ranges  Mose- 
ley's  law  does  not  hold  within  the  limits  of  experimental 
error,  there  is  undoubtedly  much  significance  to  be 
attached  to  this  simple  relation. 

Radioactivity. — The  year  following  the  discovery  of 
X-rays,  Becquerel  found  that  a  photographic  plate 
is  similarly  affected  by  radiations  from  uranium 
salts.  Two  years  later  the  Curies  separated  from 
pitchblende  the  very  active  elements  polonium  and 
radium.  Passage  of  the  rays  from  these  substances 
through  electric  and  magnetic  fields  revealed  the 
existence  of  three  types.  The  alpha  rays  have 
been  shown  by  Rutherford  and  his  co-workers  to  be 
positively  charged  helium  atoms ;  the  beta  rays  are  very 
rapidly  moving  electrons ;  and  the  gamma  rays  are  elec- 
tromagnetic pulses  of  the  same  nature  as  X-rays  but 
somewhat  shorter.  In  1902  Rutherford  and  Soddy 
advanced  the  theory  of  atomic  disintegration,  according 
to  which  the  emission  of  a  ray  is  an  indication  of  the 
breaking  down  of  the  atom  to  a  simpler  form.  Thus  in 
the  radioactive  substances  there  is  going  on  before  our 


A  CENTURY'S  PROGRESS  IN  PHYSICS     359 

eyes  a  continual  transformation  of  one  element  into 
another,  a  change,  by  the  way,  which  appears  to  be  in  no 
slightest  degree  either  hastened  or  delayed  by  changes  in 
temperature  (H.  L.  Bronson,  20,  60,  1905)  or  external 
electrical  condition  of  the  radioactive  element.  Uranium 
is  the  progenitor  of  a  long  line  of  descendants,  of  which 
radium  was  supposed  for  some  time  to  be  the  first  mem- 
ber. Boltwood  (25,  365,  1908)  of  Yale,  however,  showed 
that  the  slow  growth  of  radium  in  uranium  solutions  is 
incompatible  with  this  assumption,  and  soon  isolated  an 
intermediate  product  which  he  named  ionium.  Radium 
itself  disintegrates  into  a  gas  known  as  radium  emana- 
tion, which  in  turn  gives  rise  to  a  succession  of  other 
products.  Analyses  by  Boltwood  (23,  77, 1907)  of  radio- 
active minerals  from  the  same  locality  show  such  a  con- 
stant ratio  between  the  amounts  of  uranium  and  lead 
present  that  it  is  natural  to  conclude  that  lead  is  the  end 
product  of  the  series.  This  hypothesis  is  confirmed  by 
the  fact  that  the  oldest  rocks  show  relatively  the  greatest 
amounts  of  this  element. 

In  addition  to  the  Ionium-Radium  series  two  others 
have  been  discovered.  Of  these  Boltwood's  (25, 269, 1908) 
investigations  seem  to  indicate  that  the  one  which  starts 
with  actinium  is  a  collateral  branch  of  the  radium  series 
and  comes  from  the  same  parent  uranium.  The  other 
begins  with  thorium  and  comprises  ten  members.  As 
yet  the  end  products  of  the  actinium  and  thorium  series 
have  not  been  identified,  although  there  is  some  reason 
for  believing  that  an  isotope  of  lead  may  be  the  final 
member  of  the  latter. 

As  the  amount  of  a  radioactive  element  which  disin- 
tegrates in  a  given  time  is  proportional  to  the  total  mass 
present,  an  infinite  time  would  be  required  for  the  sub- 
stance to  be  completely  transformed.  Hence  the  life  of 
such  an  element  is  measured  by  the  half  value  period,  or 
time  taken  for  half  the  initial  mass  to  disintegrate. 
This  time  varies  widely  for  different  radioactive  sub- 
stances, ranging  from  a  small  fraction  of  a  second  for 
actinium  A  to  five  billion  years  for  uranium.  Bolt- 
wood's  (25,  493,  1908)  original  determination  of  the  life 
of  radium  from  the  rate  of  its  growth  in  a  solution  con- 
taining ionium  gave  2000  years  as  its  result,  although 


360  A  CENTURY  OF  SCIENCE 

recent  measurements  by  Miss  Gleditsch  (41,  112,  1916) 
agree  more  closely  with  the  value  1760  years  obtained  by 
Rutherford  and  Geiger  from  the  number  of  alpha  parti- 
cles emitted. 

Under  the  action  of  X-rays  or  the  radiations  from 
radioactive  substances,  gases  acquire  a  conductivity 
which  has  been  attributed  by  Thomson  and  Rutherford 
to  the  formation  of  ions.  Zeleny  has  found  that  ions  of 
opposite  sign  have  somewhat  different  mobilities  in  an 
electric  field,  and  experiments  of  Wellisch  (39,  583, 1915) 
show  that  at  low  pressures  some  of  the  negative  ions  are 
electrons.  T.  S.  Taylor  (26, 169, 1908  et  seq.)  and  Duane 
(26,  464,  1908)  have  investigated  the  ionization  produced 
by  alpha  particles,  and  Bumstead  (32,  403,  1911  et  seq.) 
has  studied  the  emission  of  electrons  from  metals  which 
are  bombarded  by  these  rays.  The  investigations  of 
Franck  and  Hertz,  and  McLennan  and  Henderson,  show 
a  significant  relation  between  the  ionizing  potential 
(energy  which  must  be  possessed  by  an  electron  in  order 
to  produce  an  ion  on  colliding  with  an  atom)  and  a  quan- 
tity, to  be  considered  later  in  more  detail,  which  has  been 
introduced  by  Planck  into  the  theory  of  radiation. 

Methods  of  Science. — Scientific  progress  seems  to  fol- 
low a  more  or  less  clearly  defined  path.  Experimenta- 
tion brings  to  light  the  hidden  processes  of  nature,  and 
hypotheses  are  advanced  to  correlate  the  facts  discov- 
ered. As  more  and  more  phenomena  are  found  to  fit  into 
the  same  scheme,  the  hypotheses  at  first  proposed  tenta- 
tively, although  often  only  after  extensive  alterations, 
become  firmly  established  as  theories.  Finally  there  may 
appear  a  fundamental  clash  between  two  theories,  each  of 
which  in  its  respective  domain  seems  to  represent  the  only 
possible  manner  in  which  a  large  group  of  phenomena 
can  be  correlated.  The  maze  becomes  more  perplexing 
at  every  step.  At  last  a  genius  appears  on  the  scene, 
approaches  the  problem  from  a  new  and  unsuspected 
point  of  view,  and  the  paradox  vanishes.  Such  changes 
in  point  of  view  are  the  milestones  which  mark  the 
progress  of  science.  That  science  is  stagnant  whose 
only  function  is  to  collect,  classify  and  correlate  vast 
stores  of  experimental  data.  The  sign  of  vitality  is  the 
existence  of  clearly  defined  and  fundamental  problems 


A  CENTURY'S  PROGRESS  IN  PHYSICS     361 

any  possible  solution  of  which  seems  irreconcilable  with 
the  most  basic  truths  of  the  science  in  question.  The 
greater  the  paradox  grows,  the  more  certain  the  advent 
of  a  new  point  of  view  which  will  bring  one  step  nearer 
the  comprehensive  picture  of  nature  which  is  the  goal  of 
natural  philosophy. 

The  Ether. — From  the  earliest  times  philosophers  have 
been  attracted  by  the  possibility  of  explaining  physical 
phenomena  in  terms  of  an  all-pervading  medium.  So 
strong  had  this  tendency  become  by  the  middle  of  the 
nineteenth  century  that  the  English  school  of  physicists 
were  attributing  rigidity,  density  and  nearly  all  the  prop- 
erties of  material  media  to  the  ether.  In  fact  most 
physicists  seemed  to  have  forgotten  that  no  experiment 
had  ever  given  direct  evidence  of  the  existence  of  such  a 
medium.  Not  until  the  first  decade  of  the  twentieth  cen- 
tury was  it  realized  that  the  experimental  evidence  actu- 
ally pointed  in  quite  the  opposite  direction,  and  that  a 
new  point  of  view  was  needed  in  dealing  with  those  phe- 
nomena of  light  and  electromagnetism  which  had  been 
previously  described  in  terms  of  a  universal  medium. 
Some  account  of  the  development  of  the  ether  theory 
and  of  the  origin  and  growth  of  the  point  of  view  which 
has  its  principal  exemplification  in  the  principle  of  rela- 
tivity is  essential  for  an  understanding  of  present  ten- 
dencies in  formulating  a  philosophic  basis  for  scientific 
thought. 

In  the  time  of  Newton  and  for  a  century  after  there  was 
much  controversy  between  the  adherents  of  two  irrecon- 
cilable theories  of  light.  Hooke  had  suggested  that 
light  is  a  wave  motion  traveling  through  a  homogeneous 
medium  which  fills  all  space,  and  Huygens  had  shown 
that  the  law  of  refraction  can  be  deduced  at  once  from 
this  hypothesis  if  it  is  assumed  that  the  velocity  of  light 
in  a  transparent  body  is  less  than  that  in  free  ether. 
However,  Newton,  impressed  by  the  fact  that  a  ray 
obtained  by  double  refraction  in  Iceland  spar  differs  from 
a  ray  of  ordinary  light  just  as  a  rod  of  rectangular  cross 
section  differs  from  one  of  circular  cross  section,  and 
seeing  no  way  of  explaining  this  dissymmetry  in  terms 
of  a  wave  motion  analogous  to  longitudinal  sound  waves, 
adhered  to  the  view  that  light  consists  of  infinitesimal 


362  A  CENTUEY  OF  SCIENCE 

particles  shot  out  from  the  luminous  body  with  enormous 
velocities.  So  great  was  his  reputation  on  account  of  his 
discoveries  in  other  fields  that  this  theory  of  light  held 
sway  among  his  contemporaries  and  successors  until  the 
labors  of  Young  and  Fresnel  at  the  beginning  of  the 
nineteenth  century  definitely  established  the  undulatory 
theory.  However,  in  spite  of  the  fact  that  a  corpuscular 
theory  of  light  made  the  assumption  of  an  ether  unneces- 
sary in  so  far  as  the  simpler  of  the  observed  phenomena 
are  concerned,  even  Newton  postulated  the  existence  of 
such  a  medium,  partly  in  order  to  explain  the  more  com- 
plicated results  of  experiments  in  light,  and  partly  in 
order  to  provide  a  vehicle  for  the  propagation  of  gravi- 
tational forces. 

Now  an  ether,  if  it  is  to  explain  anything  at  all,  must 
have  at  least  some  of  the  simpler  properties  of  material 
media.  The  most  fundamental  of  these,  perhaps,  is  posi- 
tion in  space.  As  a  first  approximation  in  explaining 
optical  phenomena  on  the  earth's  surface,  the  earth 
might  be  supposed  to  be  at  rest  relative  to  the  ether. 
But  the  establishment  of  the  Copernican  system  made  the 
sun  the  center  of  the  solar  system  and  gave  the  earth  an 
orbital  speed  of  eighteen  miles  a  second.  It  may  be 
remarked  parenthetically  that  the  speed  of  a  point  on  the 
equator  due  to  the  earth's  diurnal  rotation  is  quite  insig- 
nificant compared  to  its  orbital  velocity.  Hence  as  a 
second  approximation  the  sun  might  be  considered  at 
rest  relative  to  the  ether  and  the  earth  as  moving 
through  this  unresisting  medium. 

The  first  indication  of  this  motion  lay  in  the  discovery 
of  aberration  by  the  British  astronomer  Bradley  in  1728. 
Bradley  noticed  that  stars  near  the  pole  of  the  ecliptic 
describe  small  circles  during  the  course  of  a  year,  while 
those  in  the  plane  of  the  ecliptic  vibrate  back  and  forth 
in  straight  lines,  stars  in  intermediate  positions  describ- 
ing ellipses.  The  surprising  thing,  however,  was  that 
the  time  taken  to  complete  one  of  these  small  orbits  is  in 
all  cases  exactly  a  year.  Bradley  concluded  that  the 
phenomenon  is  in  some  way  dependent  on  the  earth's 
motion  around  the  sun,  and  he  was  not  long  in  reaching 
the  correct  explanation.  For  suppose  the  earth  to  be  at 
rest.     Then  in  observing  a  star  at  the  pole  of  the  ecliptic 


A  CENTURY'S  PROGEESS  IN  PHYSICS     363 

it  would  be  necessary  to  keep  the  axis  of  the  telescope 
exactly  at  right  angles  to  the  plane  of  the  earth's  orbit. 
However,  as  the  earth  is  in  motion,  the  telescope  must  be 
pointed  a  little  forward,  just  as  in  walking  rapidly 
through  the  rain  an  umbrella  must  be  inclined  forward  so 
as  to  intercept  the  raindrops  which  would  otherwise  fall 
on  the  spot  to  be  occupied  at  the  end  of  the  next  step. 
The  angle  through  which  the  telescope  has  to  be  tilted  is 
known  as  the  angle  of  aberration,  and  the  tangent  of  this 
angle  may  easily  be  shown  to  be  equal  to  the  ratio  of  the 
velocity  of  the  earth  to  the  velocity  of  light.  Knowing 
the  velocity  of  the  earth,  the  velocity  of  light  can  then  be 
calculated.  This  method  was  one  of  the  first  of  obtaining 
the  value  of  this  important  quantity. 

More  recently,  terrestrial  methods  of  great  precision 
have  been  devised  for  measuring  the  velocity  of  light. 
The  most  accurate  of  these  is  that  employed  by  the 
French  physicist  Foucault  in  1862.  A  ray  of  light  is 
reflected  by  a  rotating  mirror  to  a  fixed  mirror  placed  at 
some  distance,  which  in  turn  reflects  the  ray  back  to 
the  moving  mirror.  The  latter,  however,  has  turned 
through  a  small  angle  during  the  time  elapsed  since  the 
first  reflection,  and  consequently  the  direction  of  the  ray 
on  returning  to  the  source  is  not  quite  opposite  to  that  in 
which  it  had  started  out.  This  deviation  in  direction  is 
determined  from  the  displacement  of  the  image  formed 
by  the  returning  light,  and  from  it  the  velocity  of  light 
is  calculated.  In  order  to  make  the  deflection  appreci- 
able the  distance  between  the  two  mirrors  should  be  very 
great.  As  originally  arranged  by  Foucault,  it  was 
found  impractical  to  make  this  distance  greater  than 
twenty  meters,  and  consequently  the  displacement  of  the 
image  was  less  than  a  millimeter.  Such  a  small  deflection 
limited  the  accuracy  of  the  experiment  to  one  percent. 
In  1879,  however,  Michelson  (18,  390,  1879),  then  a  mas- 
ter in  the  United  States  Navy,  improved  Foucault 's  opti- 
cal arrangements  to  such  an  extent  that  he  was  able  to 
use  a  distance  of  nearly  seven  hundred  meters  between 
the  two  mirrors.  With  a  rate  of  two  hundred  and  fifty- 
seven  revolutions  a  second  for  the  rotating  mirror,  the 
displacement  obtained  was  over  thirteen  centimeters. 
This  experiment  gave  299,910  kilometers  a  second  for 


364  A  CENTURY  OF  SCIENCE 

the  velocity  of  light,  with  a  probable  error  of  one  part  in 
ten  thousand.  Later  investigations  by  Newcomb  and 
Michelson  (31,  62,  1886)  gave  substantially  the  same 
result.  So  great  has  been  the  accuracy  of  these  terres- 
trial determinations  that  recent  practice  has  been  to  cal- 
culate from  them  and  the  angle  of  aberration  the  earth's 
orbital  velocity,  and  hence  the  distance  of  the  earth  from 
the  sun.  This  indirect  method  of  measuring  the  astro- 
nomical unit  has  a  probable  error  no  greater  than  the  best 
parallax  methods  of  the  astronomer.  (J.  Lovering,  36, 
161, 1863.) 

Aberration  is  a  first  order  effect,  i.  e.,  it  depends  upon 
the  first  power  of  the  ratio  of  the  velocity  of  the  earth  to 
the  velocity  of  light,  and  at  first  sight  it  seemed  to  prove 
conclusively  that  the  earth  must  be  in  motion  relative  to 
the  luminif erous  medium.  Other  questions  had  to  be  set- 
tled, however,  and  one  of  these  was  whether  or  not  light 
coming  from  a  star  would  be  refracted  differently  when 
passing  through  optical  instruments  from  light  which 
had  a  terrestial  origin.  Arago  subjected  the  matter  to 
experiment,  and  concluded  that  in  every  respect  the  light 
from  a  star  behaved  as  if  the  earth  were  at  rest  and  the 
star  actually  occupied  the  position  which  it  appears  to 
occupy  on  account  of  aberration.  Finally  optical  exper- 
iments with  terrestrial  sources  seemed  to  be  in  no  way 
affected  by  the  motion  of  the  earth  through  the  ether. 

In  order  to  account  for  these  facts  Fresnel  advanced 
the  following  theory.  To  explain  the  refraction  that 
takes  place  when  light  enters  a  transparent  body,  it  is 
necessary  to  assume  that  light  waves  travel  more  slowly 
through  matter  than  in  free  ether.  Now  the  velocity  of 
sound  is  known  to  vary  inversely  with  the  square  root  of 
the  density  of  the  material  medium  through  which  it 
passes.  Hence  it  is  natural  to  assume  that  ether  is  con- 
densed inside  material  objects  to  such  an  extent  that 
this  same  relation  connects  its  density  with  the  velocity 
of  light  traveling  through  it.  But  when  a  lens  or  prism 
is  set  in  motion,  Fresnel  supposed  it  to  carry  along  only 
the  excess  ether  which  it  contains,  ether  of  the  normal 
density  remaining  behind.  This  assumption  suffices  to 
explain  Arago 's  results,  and  yet  fits  in  with  the  phenom- 
enon of  aberration.    It  gives  for  light  traveling  in  the 


A  CENTURY'S  PROGRESS  IN  PHYSICS     365 

direction  of  motion  through  a  moving  material  medium 
of  index  of  refraction  n  an  absolute  velocity  greater  than 
that  when  the  medium  is  at  rest  by  an  amount 


i'-^h 


which  is  only  a  fraction  of  the  velocity  v  which  would 
have  to  be  added  if  convected  matter  carried  along  all 
the  ether  which  resides  within  it.  This  expression  was 
tested  directly,  first  by  Fizeau  in  1851,  and  later  by 
Michelson  and  Morley  (31,  377,  1886)  in  this  country. 
The  experiment  consists  in  bifurcating  a  beam  of  light, 
passing  one  half  in  one  direction  and  the  other  in  the 
opposite  direction  through  a  stream  of  running  water. 
On  reuniting  the  two  rays  the  usual  interference  fringes 
are  produced.  Reversing  the  direction  of  motion  of  the 
water  causes  the  fringes  to  shift,  and  from  the  amount  of 
this  shift  the  velocity  imparted  to  the  light  by  the  motion 
of  the  stream  is  computed.  The  divergence  between  the 
experimental  value  of  this  quantity  and  that  calculated 
from  FresnePs  coefficient  of  entrainment  was  found  by 
Michelson  and  Morley  to  be  less  than  one  percent,  which 
'was  about  their  experimental  error.  Thus  FresnePs 
expression  for  the  velocity  of  light  in  a  moving  medium  is 
entirely  confirmed  by  experiment.  The  derivation  of  it 
accepted  to-day,  however,  is  very  different  from  his  orig- 
inal deduction. 

It  has  been  noted  that  the  phenomena  of  polarization 
led  Newton  to  reject  the  wave  theory  of  light.  The  only 
type  of  wave  known  to  him  was  the  longitudinal  wave, 
in  which  the  vibrations  of  the  particles  of  the  medium  are 
in  the  same  direction  as  that  of  propagation  of  the  wave, 
and  it  was  impossible  to  suppose  that  such  a  wave  could 
have  different  properties  in  different  directions  at  right 
angles  to  the  line  in  which  it  is  advancing.  But  in  1817 
Young  suggested  that  this  inconsistency  between  the 
wave  theory  and  the  facts  of  polarization  could  be 
removed  by  supposing  the  vibrations  constituting  light  to 
be  executed  at  right  angles  to  the  direction  of  propaga- 
tion. ^  Thus  in  ordinary  light  the  vibrations  are  to  be 
conceived  as  taking  place  haphazard  in  all  directions  in 
the  plane  perpendicular  to  the  ray,  while  in  plane  polar- 


366  A  CENTURY  OF  SCIENCE 

ized  light  these  vibrations  are  confined  to  a  single 
direction.  This  supposition  explained  so  many  of  the 
puzzling  results  of  experiment,  that  it  was  accepted  at 
once  and  led  to  the  complete  vindication  of  the  undula- 
tory  theory. 

Elastic  Solid  Theory. — Shortly  afterwards  Poisson 
succeeded  in  solving  the  differential  equation  which 
determines  the  motion  of  a  wave  through  an  elastic 
medium.  His  solution  shows  that  such  a  medium  is 
capable  of  transmitting  two  types  of  wave — one  longi- 
tudinal, the  other  transverse.  If  k  denotes  the  volume 
elasticity,  v  the  rigidity  and  p  the  density  of  the  medium, 
the  velocities  of  the  two  waves  are  respectively 


|/i+±?       and       |/^ 


Now  a  solid  has  both  compressibility  and  rigidity, 
and  transmits  in  general  both  types  of  wave.  A 
fluid,  on  the  other  hand,  on  account  of  its  lack  of 
rigidity,  cannot  support  a  transverse  vibration.  Hence 
it  was  natural  that  Green,  in  searching  for  a  dynamical 
explanation  of  the  ether,  should  have  proposed  in  a  paper 
read  before  the  Cambridge  Philosophical  Society  in 
1837  that  the  ether  has  the  elastic  properties  of  a  solid. 
One  great  difficulty  presented  itself;  disturbances 
inside  an  elastic  solid  must  give  rise  to  compressional  as 
well  as  to  transverse  waves.  But  no  such  thing  as  a 
compressional  wave  had  been  found  in  the  experimental 
study  of  light.  Green  attempted  to  overcome  this  diffi- 
culty by  attributing  an  infinite  volume-elasticity  to  the 
ether.  The  expression  above  shows  that  longitudinal 
waves  originating  in  such  an  incompressible  medium 
would  be  carried  away  with  an  infinite  velocity,  and  it 
may  be  shown  that  the  energy  associated  with  them 
would  be  infinitesimal  in  amount.  The  next  step  was  to 
calculate  the  coefficients  of  transmission  and  reflection 
for  light  passing  from  one  material  medium  to  another. 
Here  the  elastic  solid  theory  is  not  altogether  successful. 
If  the  ether  is  supposed  to  have  different  densities  in  the 
two  media,  as  in  FresnePs  theory,  but  the  same  rigidity, 
certain    of   these    coefficients    fail   to    give   the   values 


A  CENTURY'S  PROGRESS  IN  PHYSICS     367 

demanded  by  experiment,  while  if  the  densities  are 
assumed  the  same  but  the  rigidities  different,  other  of  the 
coefficients  have  discordant  values.  In  connection  with 
the  phenomena  of  double  refraction  even  more  serious 
difficulties  are  encountered. 

Electromagnetic  Theory. — It  was  beginning  to  be  felt 
that  an  ether  must  explain  more  than  the  phenomena  of 
light,  for  Faraday's  conception  of  electromagnetic 
action  as  carried  on  through  the  agency  of  a  medium 
had  added  greatly  to  its  functions.  Finally  Maxwell's 
demonstration  that  electromagnetic  waves  are  propa- 
gated with  the  velocity  of  light  made  the  theory 
of  light  into  a  subdivision  of  electrodynamics.  Maxwell 
himself  did  not  apply  electromagnetic  theory  to  the 
explanation  of  reflection  and  refraction.  This  defi- 
ciency, however,  was  remedied  by  Lorentz  in  1875.  The 
results  obtained,  as  well  as  those  for  double  refraction 
(J.  W.  Gibbs,  23,  262,  1882  et  seq.),  and  metallic  reflec- 
tion (L.  P.  Wheeler,  32,  85,  1911),  provided  a  complete 
vindication  of  the  electromagnetic  theory  of  light.  This 
is  all  the  more  significant  when  the  extreme  precision 
obtainable  in  optical  experiments  is  taken  into  account. 
For  instance,  Hastings  (35,  60,  1888)  has  tested  Huy- 
gens'  construction  for  double  refraction  in  Iceland  spar 
and  found  that  **the  difference  between  a  measured  index 
of  refraction  ...  at  an  angle  of  30°  with  the  crystalline 
axis,  and  the  index  calculated  from  Huygens'  law  and 
the  measured  principal  indices  of  refraction"  is  a  matter 
of  only  4-5  units  in  the  sixth  decimal  place.  Since  Max- 
well's time  the  gamut  of  electromagnetic  waves  has  been 
steadily  extended.  The  shortest  Hertzian  waves  merge 
almost  imperceptibly  into  the  longest  heat  waves  of  the 
infra-red,  and  from  there  the  known  spectrum  runs  con- 
tinuously through  the  visible  region  to  the  short  waves 
of  the  extreme  ultra-violet  recently  disclosed  by  Lyman. 
Here  there  is  a  short  gap  until  soft  X-rays  are  reached, 
and  finally  the  domain  of  radiation  comes  to  an  end  with 
gamma  rays  a  billionth  of  a  centimeter  in  length. 

Maxwell's  ether  was  not  a  dynamical  ether  in  the  sense 
of  Green's  elastic  solid  medium.  In  spite  of  the  fact  that 
Maxwell  was  always  active  in  devising  mechanical  ana- 


368  A  CENTURY  OF  SCIENCE 

logues  to  illustrate  the  phenomena  of  electromagnetism, 
he  was  never  enthusiastic  over  the  speculations  of  the 
advocates  of  a  dynamical  ether.  The  electrodynamic  equa- 
tions provided  an  accurate  representation  of  the  electric 
and  magnetic  fields,  and  bevond  that  he  felt  it  was  need- 
less to  go.  That  Gibbs  (23,  475,  1882)  held  the  same 
view  is  made  evident  by  the  closing  paragraphs  of  a 
paper  in  which  he  shows  that  the  electromagnetic  theory 
of  light  accounts  in  minutest  detail  for  the  intricate  phe- 
nomena accompanying  the  passage  of  light  through  cir- 
cularly polarizing  media.     He  says : 

**The  laws  of  the  propagation  of  light  in  plane  waves,  which 
have  thus  been  derived  from  the  single  hypothesis  that  the  dis- 
turbance by  which  light  is  transmitted  consists  of  solenoidal 
electrical  fluxes,  .  .  .  are  essentially  those  which  are  received 
as  embodying  the  results  of  experiment.  In  no  particular,  so 
far  as  the  writer  is  aware,  do  they  conflict  with  the  results  of 
experiment,  or  require  the  aid  of  auxiliary  and  forced  hypotheses 
to  bring  them  into  harmony  therewith. 

In  this  respect  the  electromagnetic  theory  of  light  stands  in 
marked  contrast  with  that  theory  in  which  the  properties  of  an 
elastic  solid  are  attributed  to  the  ether, — a  contrast  which  was 
very  distinct  in  Maxwell's  derivation  of  Fresnel's  laws  from 
electrical  principles,  but  becomes  more  striking  as  we  follow  the 
subject  farther  into  its  details,  and  take  account  of  the  want  of 
absolute  homogeneity  in  the  medium,  so  as  to  embrace  the 
phenomena  of  the  dispersion  of  colors  and  circular  and  elliptical 
polarization." 

Further  Dynamical  Theories. — Kelvin,  however,  was 
not  satisfied  with  this  type  of  ether.  To  him  djoiamics 
was  the  foundation  of  all  physical  phenomena,  and  noth- 
ing could  be  said  to  be  explained  until  a  mechanical  model 
was  provided.  So  he  returned  to  the  elastic  solid  theory, 
and  developed  the  consequences  of  the  assumption, 
already  made  use  of  by  Cauchy,  that  the  ether  has  a  nega- 
tive volume  elasticity  of  such  a  value  as  to  make  the 
velocity  of  the  compressional  wave  zero.  In  order  to 
prevent  such  an  ether  from  collapsing  it  is  necessary  to 
assume  that  it  is  rigidly  attached  at  its  boundaries  and 
that  cavities  cannot  be  formed  at  any  point  in  its  interior. 
Now  Gibbs  (37,  129,  1889)  has  pointed  out  the  remark- 


A  CENTURY^S  PROGRESS  IN  PHYSICS     369 

able  fact  that  the  equations  describing  the  motion  of 
Kelvin's  quasi-labile  ether  are  of  exactly  the  same  form 
as  the  electromagnetic  equations.  Electric  displacement 
is  represented  by  an  actual  displacement  of  the  ether, 
magnetic  intensity  by  a  rotation.  Hence  everything 
which  can  be  explained  by  the  electrodynamic  equations 
finds  an  analogue  in  terms  of  Kelvin's  ether.  Still 
another  type  of  dynamic  ether  which  fits  the  known  facts 
was  proposed  by  McCullagh  and  perfected  by  Larmor. 
In  this  ether  a  rotational  elasticity  is  premised,  such  as 
would  exist  if  each  particle  of  the  medium  consisted  of 
three  rigidly  connected  gyrostats  with  mutually  perpen- 
dicular axes.  In  this  ether  electrical  displacements  cor- 
respond to  rotations,  and  magnetic  strains  to  etherial  dis- 
placement. 

A  New  Point  of  View. — While  tTie  dynamical  school 
was  still  dominant  in  England,  another  point  of  view 
was  developing  on  the  continent.  Kirchhoff  denied 
that  it  was  the  province  of  science  to  provide  mechanical 
explanations  of  the  ether  and  electrodynamic  phenomena 
such  as  Kelvin  conceived  to  be  necessary  in  order  to  make 
these  phenomena  intelligible.  Kirchhoif's  contention 
was  that  the  object  of  science  is  purely  descriptive, — 
phenomena  must  be  observed,  classified,  and  mutual  con- 
nections described  by  the  fewest  number  of  differential 
equations  possible.  Mach  expressed  the  same  idea 
somewhat  more  concisely  when  he  asserted  that  the  aim 
of  science  is  ** economy  of  thought."  For  instance,  in 
the  time  of  Newton,  planetary  motions  could  be  described 
quite  satisfactorily  by  means  of  the  three  laws  of  Kepler. 
The  motion  of  falling  bodies  on  the  earth's  surface  had 
been  described  with  a  fair  degree  of  accuracy  by  Galileo. 
The  value  of  Newton's  law  of  gravitation,  however,  lay  in 
the  fact  that  this  great  generalization  made  it  possible  to 
describe  these  and  many  other  types  of  motion  by  a 
single  simple  formula,  instead  of  leaving  each  to  be  gov- 
erned by  a  number  of  separate  and  apparently  unrelated 
laws.  The  importance  of  such  a  generalization  is  meas- 
ured by  the  economy  of  thought  which  it  introduces. 

Electron  Theory. — The  electron  theory  was  leading  to 
a  reversal  of  Kelvin's  idea  that  dynamical  principles 


370 


A  CENTURY  OF  SCIENCE 


must  underlie  electrodynamics.  Lorentz  had  shown  that 
a  rigorous  solution  of  the  electrodynamic  equations  did 
away  entirely  with  Maxwell's  displacement  current,  but 
made  the  electromagnetic  field  at  a  point  in  space  depend 
not  upon  the  distribution  of  charges  and  currents  at  the 
same  instant,  but  at  a  time  earlier  sufficient  to  allow  the 
effect  to  travel  with  the  velocity  of  light  from  the  charges 
and  currents  producing  the  field  to  the  point  at  which  the 
electric  and  magnetic  intensities  are  to  be  found.  The 
position  of  a  charge  or  current  element  at  this  earlier  time 
he  denoted  its  ** effective  position.''  The  effective  distri- 
bution, then,  is  that  actually  seen  by  an  observer  stationed 


Fig.  1. 


Fig.  2. 


Fig.  3. 


at  the  point  under  consideration  at  the  instant  for  which 
the  intensity  of  the  electromagnetic  field  is  to  be  deter- 
mined. This  solution  of  the  electrodynamic  equations 
led  in  turn  to  rigorous  expressions  for  the  electric  and 
magnetic  intensities  produced  by  a  very  small  charged 
particle,  such  as  an  electron.  Fig.  1  shows  the  electro- 
static field  produced  by  a  charged  particle  at  rest.  The 
lines  of  force  spread  out  radially  and  uniformly  in  all 
directions.  In  fig.  2  the  electron  is  supposed  to  have  a 
velocity  v  horizontally  to  the  right  of  an  amount  smaller 
than,  though  comparable  with,  the  velocity  of  light  c. 
It  is  seen  that  the  lines  of  electric  force  still  diverge 
radially  from  the  charge,  but  are  crowded  in  the  equato- 
rial plane  and  spread  apart  in  the  polar  regions.  The 
dissymmetry  grows  as  the  velocity  increases  until  if  the 
velocity  of  light  should  be  reached  the  field  would  be 
entirely  concentrated  in  a  plane  at  right  angles  to  the 
direction  of  motion.    Now  it  may  be  shown  that  fig.  2  is 


A  CENTURY'S  PROGRESS  IN  PHYSICS     371 

obtainable  from  fig.  1  by  reducing  dimensions  in  the 
direction  of  motion  in  the  ratio  of 

^1  —  ^»  :  1,     where    p~-. 

For  a  uniformly  convected  electric  field  differs  from  an 
electrostatic  field  only  in  that  the  dimensions  in  the  direc- 
tion of  motion  are  contracted  in  this  particular  ratio. 
Fig.  3  represents  the  electric  field  of  a  charged  particle 
which  has  a  uniform  acceleration  to  the  right.  Consider 
Faraday's  analogy  between  lines  of  force  and  stretched 
elastic  bands.  The  symmetry  of  the  first  two  figures 
shows  that  in  neither  of  these  cases  would  there  be  a 
resultant  force  on  the  charged  particle.  But  in  the  third 
figure  it  is  obvious  that  a  force  to  the  left  is  exerted  on 
the  charge  by  its  own  field.  Calculation  shows  this  force 
to  be  proportional  in  magnitude  to  the  acceleration.  Let 
it  be  postulated  that  the  resultant  force  on  a  charged 
particle  is  always  zero.  Then  if  F  is  the  applied  force, 
the  force  on  the  particle  due  to  the  reaction  of  its  field 
will  be  —  mf,  where  /  stands  for  the  acceleration  and  m 
is  a  positive  constant,  and  we  have  the  fundamental 

equation  of  dynamics  • 

F  —  mf  =  0 

Hence,  instead  of  admitting  Kelvin's  contention  that  all 
physical  phenomena  must  be  given  a  mechanical  explana- 
tion, it  would  seem  more  logical  to  assert  that  electro- 
dynamics actually  underlies  mechanics. 

Calculation  shows  the  electromagnetic  mass  m  to  vary 
inversely  with  the  radius  of  the  charged  particle.  Now 
Thomson's  experiments  made  it  possible  to  calculate  the 
mass  of  an  electron.  Hence  its  radius  can  be  computed, 
and  is  found  to  be  about  2(10)"^^  part  of  a  centimeter,  or 
one  fifty-thousandth  part  of  the  radius  of  the  atom. 
Since  numbers  so  small  convey  little  meaning,  consider 
the  following  illustration,  due,  in  part,  to  Kelvin. 
Imagine  a  single  drop  of  water  to  be  magnified  until  it  is 
as  large  as  the  earth.  The  individual  atoms  would  then 
have  the  size  of  baseballs.  Now  magnify  one  of  these 
atoms  until  it  is  comparable  in  size  with  St.  Peter's 
cathedral  at  Rome.  The  electrons  within  the  atom  would 
appear  as  a  few  grains  of  sand  scattered  about  the  nave. 


372  A  CENTUEY  OF  SCIENCE 

This  separation  between  the  constituent  electrons  of  the 
atom, — so  great  in  comparison  with  their  dimensions, — 
explains  how  alpha  particles  can  be  shot  by  the  billion 
through  thin-walled  glass  tubing  without  leaving  any 
holes  behind  or  impairing  in  the  slightest  degree  the  high 
vacuum  within  the  tube.  The  much  smaller  high-speed 
beta  particles  pass  through  an  average  of  ten  thousand 
atoms  without  even  coming  near  enough  to  one  of  the 
component  electrons  to  detach  it  and  form  an  ion. 

Michelson-Morley  Experiment. — In  1881  Michelson 
(22,  120,  1881)  conceived  an  ingenious  and  bold  method 
of  measuring  the  orbital  motion  of  the  earth  through  the 
luminiferous  ether.  As  the  experiment  was  one  involv- 
ing considerable  expense.  Bell,  the  inventor  of  the  tele- 
phone receiver,  was  appealed  to  successfully  for  the 
funds  necessary  to  carry  it  through.  Michelson 's 
experimental  plan  was  as  follows:  A  beam  of  light 
traveling  in  the  direction  of  the  earth's  motion  strikes 
an  unsilvered  mirror  m  at  an  angle  of  45°.  Part  of  the 
light  passes  through,  the  rest  being  reflected  at  right 
angles  to  its  original  direction.  Each  ray  is  returned  by 
a  mirror  at  a  distance  I  from  m.  On  meeting  again,  the 
ray  whose  path  has  been  at  right  angles  to  the  direction 
of  the  earth's  motion  passes  on  through  the  mirror,  while 
the  other  ray  is  reflected  so  as  to  bring  the  two  in  line 
and  form  interference  fringes.  Now  consider  the  effect 
of  the  earth's  motion  on  the  paths  of  the  two  rays.  In 
fig.  4  the  earth  is  supposed  to  be  moving  to  the  right. 
The  unsilvered  mirror  m  bifurcates  a  beam  of  light  com- 
ing from  a  source  a.  By  the  time  the  ray  reflected  from 
m  has  traveled  to  the  mirror  h  and  back,  m  will  have 
moved  forward  to  m';  a  distance  2^1,  where  the  small 
quantity  (3  is  the  ratio  of  the  earth's  velocity  to  the 
velocity  of  light.  Hence  the  length  of  the  path  traversed 
by  this  ray  is  approximately 


2/(1  + 


i& 


The  other  ray  will  reach  the  mirror  c  after  the  latter  has 
moved  forward  a  distance 


A  CENTURY'S  PROGRESS  IN  PHYSICS     373 

and  on  returning  find  m  at  m'.  Hence  its  path  has  a 
length  of  roughly  21  (1  +  /?^).  The  difference  in  path  of 
the  two  rays  is  (3- 1  and  consequently  they  should  be  a 
little  out  of  phase  on  meeting  at  d.  By  rotating  the 
apparatus  clockwise  through  90°  the  directions  of  the 
two  rays  relative  to  the  earth's  motion  are  interchanged, 


and  the  interference  fringes  would  be  expected  to  shift 
an  amount  corresponding  to  a  difference  in  path  of  2  ^^  I. 
This  quantity  is  of  course  small, — p^  is  about  one  one- 
hundred  millionth, — but  so  sensitive  are  the  methods  of 
interferometry  that  Michelson  felt  confident  that  he 
would  be  able  to  detect  the  earth's  motion  through  the 
ether.  The  apparatus  consisted  of  a  table  which  could 
be  rotated  about  a  vertical  axis  in  much  the  same  way 
as  a  spectrometer  table,  and  provided  with  arms  a  meter 
long  to  carry  the  mirrors  b  and  c.  With  this  length  of 
arm  the  interference  fringes  from  sodium  light  should 
shift  by  an  amount  corresponding  to  four  hundredths  of 
a  wave  length  when  the  table  is  rotated  through  a  right 
angle.  When  the  experiment  was  first  performed  the 
apparatus  was  placed  on  a  stone  pier  in  the  Physical  Insti- 


374  A  CENTURY  OF  SCIENCE 

tute  at  Berlin.  So  sensitive  was  the  instrument  to  outside 
vibrations  that  even  after  midnight  it  was  found  impos- 
sible to  get  consistent  readings.  Finally  a  satisfactory- 
foundation  was  constructed  in  the  cellar  of  the  Astro- 
physical  observatory  at  Potsdam.  But  what  was  the 
astonishment  of  the  experimenters  to  find  that  the 
expected  shift  of  the  interference  fringes  did  not  exist! 

The  extreme  delicacy  of  the  experiment  made  it  desir- 
able to  confirm  the  result  by  repeating  it.  This  was 
done  by  Michelson  and  Morley  (34,  333,  1887)  in  1887. 
In  place  of  a  revolving  table  a  massive  slab  of  stone 
floating  on  mercury  was  used  to  carry  the  apparatus. 
This  slab  was  kept  in  constant  rotation,  the  observer 
following  it  around.  Moreover,  the  precision  of  the 
experiment  was  greatly  increased  by  reflecting  each  ray 
back  and  forth  across  the  slab  a  number  of  times  between 
leaving  and  returning  to  the  mirror  m.  The  accuracy 
attained  was  such  as  to  justify  Michelson  in  declaring 
that  if  the  effect  sought  actually  existed  it  could  not  be 
so  great  as  one-twentieth  of  its  calculated  value.  In 
1905  Morley  and  Miller^^  repeated  the  experiment  for  the 
second  time  and  succeeded  in  increasing  the  sensitiveness 
of  the  apparatus  to  a  point  such  that  a  motion  through 
the  ether  of  one-tenth  of  the  earth's  orbital  velocity 
could  have  been  detected. 

The  displacement  looked  for  in  the  Michelson-Morley 
experiment  is  known  as  a  second-order  effect  in  that  it 
depends  upon  the  square  of  the  ratio  of  the  velocity  of  the 
earth  to  that  of  light.  Michelson  at  first  considered  that 
the  negative  result  obtained  confirmed  a  theory  proposed 
by  Stokes  in  which  it  was  assumed  that  the  ether  inside 
and  near  its  surface  partakes  of  the  motion  of  the  earth, 
while  that  at  a  distance  is  practically  quiescent.  But 
there  are  many  objections  to  Stokes'  theory,  one  of  which 
was  brought  out  by  an  experiment  of  Michelson's  (3,  475, 
1897)  in  which  he  attempted  by  an  interference  method 
to  detect  a  difference  in  the  velocity  of  light  at  different 
levels  above  the  earth's  surface.  The  negative  result 
obtained  led  him  to  conclude  that  if  Stokes'  theory  were 
true  the  earth's  influence  on  the  ether  would  have  to 
extend  to  a  distance  above  its  surface  comparable  with 
its  diameter.     Meanwhile  a  more  satisfactory  explana- 


A  CENTURY'S  PROGRESS  IN  PHYSICS     375 

tion  was  forthcoming.  It  has  been  pointed  out  that  a 
uniformly  convected  electric  field  is  derivable  from  an 
electrostatic  field  by  contracting  dimensions  in  the  direc- 
tion of  motion  in  the  ratio 


Fitzgerald  and  Lorentz  showed  independently  that  if 
moving  matter  is  distorted  in  this  same  way  the  result 
obtained  by  Michelson  would  be  just  that  to  be  expected. 
For  then  the  distance  of  the  mirror  c  from  m  would  be 


instead  of  I,  and  the  path  of  the  ray  moving  parallel  to 
the  earth's  orbit 


2l{   1   + 


:-")■ 


which  is  just  that  of  the  other  ray.  Of  course  when  the 
apparatus  is  rotated  through  90°,  the  distance  of  this 
mirror  from  m  assumes  its  normal  value  again,  and  the 
distance  of  the  other  mirror  becomes  shortened.  As  all 
measurement  consists  in  comparing  the  object  to  be 
measured  with  a  standard  this  contraction  could  never 
be  detected  by  experimental  methods,  for  the  measuring 
rod  would  contract  in  exactly  the  same  ratio  as  the  body 
to  be  measured. 

In  computing  its  electromagnetic  mass  Abraham  had 
assumed  the  electron  to  be  a  uniformly  charged  rigid 
sphere  which  keeps  its  spherical  form  no  matter  how 
great  a  velocity  it  may  be  given.  He  found  that  the  mass 
increases  with  the  speed  at  very  high  velocities,  becom- 
ing infinite  as  the  velocity  of  light  is  approached,  and 
that  its  value  depends  upon  the  direction  of  the  applied 
force.  After  the  Fitzgerald-Lorentz  contraction  was 
seen  to  be  necessary  in  order  to  explain  Michelson 's 
result,  Lorentz  calculated  the  electromagnetic  mass  of  a 
charged  sphere  which  is  deformed  into  an  oblate  spheroid 
when  set  in  motion.  For  this  type  of  electron  too,  the 
mass  approaches  infinity  for  velocities  as  great  as  that  of 
light,  and  is  different  for  different  directions.  If  a 
force  is  applied  in  the  direction  of  motion  the  inertia  to 


376  A  CENTURY  OF  SCIENCE 

be  overcome  is  a  little  greater  than  when  the  force  is 
applied  at  right  angles  to  this  direction.  Thus  we 
have  to  distinguish  between  longitudinal  and  transverse 
masses.  But  the  masses  of  Lorentz's  electron  are  not 
the  same  functions  of  its  velocity  as  those  of  Abraham's. 
Kaufmann  and  after  him  Bucherer  tested  experimentally 
the  relation  between  transverse  mass  and  velocity  by 
observing  the  deflections  produced  by  electric  and  mag- 
netic fields  in  the  paths  of  high  speed  beta  particles. 
The  latter 's  work  was  such  an  ample  confirmation  of 
Lorentz's  formula  that  it  may  be  considered  as  proven 
that  a  moving  electron  at  least  suffers  contraction  in  the 
direction  of  motion  in  the  ratio 


Vi  -  /8'  :  1. 

The  electromagnetic  theory  of  light  had  proved  so 
successful  when  applied  to  bodies  at  rest  that  Lorentz 
was  anxious  to  extend  this  theory  to  the  optics  of  moving 
media.  His  problem  was  to  find  a  group  of  homogeneous 
linear  transformations  that  would  leave  the  form  of  the 
electrodynamic  equations  unchanged.  The  Michelson- 
Morley  experiment  had  shown  that  dimensions  in  the 
direction  of  motion  must  be  contracted  in  the  moving 
system,  those  at  right  angles  remaining  unaltered.  But 
Lorentz  soon  found  that  it  was  also  necessary  to  use  a 
new  unit  of  time  in  the  moving  system,  and  as  this  time 
was  found  to  depend  upon  the  position  of  the  point  at 
which  it  is  to  be  determined,  he  called  it  the  local  time. 
Lorentz 's  transformation  is  just  that  of  the  principle 
of  relativity,  but  he  did  not  succeed  in  expressing  the 
electrodynamic  equations  in  terms  of  the  new  coordinates 
and  time  in  exactly  the  same  form  as  for  a  system  at 
rest,  for  the  reason  that  he  failed  to  endow  these  new 
units  with  sufficient  reality  to  justify  him  in  using  them 
when  it  came  to  transforming  the  velocity  term  involved 
in  an  electric  current. 

Principle  of  Relativity. — In  1905  appeared  in  the 
Annalen  der  Physik^*  a  paper  destined  to  alter  entirely 
the  point  of  view  from  which  problems  in  light  and  elec- 
tromagnetic theory  are  to  be  approached.  The  author 
was  Albert  Einstein,  of  Berne,  Switzerland,  a  young  man 


A  CENTURY'S  PROGRESS  IN  PHYSICS     377 

of  twenty-six  who  had  already  made  a  number  of  notable 
contributions  to  theoretical  physics. 

The  principle  of  relativity  proposed  by  Einstein  was 
by  no  means  new  to  students  of  dynamics.  Newton's 
first  two  laws  of  motion  express  very  clearly  the  fact  that 
in  mechanics  all  motion  is  relative.  Force  is  propor- 
tional to  acceleration,  and  the  relation  between  the  two 
is  the  same  whether  the  motion  under  consideration  is 
referred  to  fixed  axes  or  to  axes  moving  with  a  constant 
velocity.  But  in  connection  with  the  phenomena  of  light 
and  electromagnetism  the  case  seemed  to  be  quite  differ- 
ent. There  everything  was  referred  to  a  fixed  ether,  and 
even  though  Lorentz  had  found  a  set  of  transformations 
which  left  the  electrodymanic  equations  practically 
unchanged,  he  continued  to  think  in  terms  of  an  ether. 
So  physicists  were  not  a  little  startled  when  Einstein 
postulated  that  no  experiment,  practical  or  ideal,  could 
ever  distinguish  between  two  systems  in  such  a  manner 
as  to  warrant  the  assertion  that  one  of  them  is  at  rest 
and  the  other  in  motion.  All  motion  is  relative,  and  the 
laws  governing  physical,  chemical  and  biological  phe- 
nomena are  the  same  in  terms  of  the  units  of  one  system 
as  in  terms  of  those  of  any  other. 

Einstein  next  considers  some  very  fundamental  ques- 
tions. What  do  we  mean  when  we  say  that  two  events, 
one  at  A  and  the  other  at  a  point  B  far  from  A,  occur  at 
the  same  time?  Obviously  the  expression  has  no  signi- 
ficance unless  synchronous  clocks  are  stationed  at  the 
two  points.  But  how  is  it  to  be  determined  whether  or 
not  these  two  clocks  are  synchronous  ?  If  instantaneous 
communication  could  be  established  between  A  and  B 
the  matter  would  be  simple  enough.  Since  no  infinite 
velocity  of  transmission  is  available,  however,  let  a  light 
wave  be  sent  from  A  to  B  and  returned  to  A  immediately 
upon  its  arrival.  If  the  time  indicated  by  the  clock  at 
B  when  the  signal  is  received  is  half  way  between  that  at 
which  it  left  A  and  the  time  at  which  it  arrives  on  its 
return,  then  the  two  clocks  may  be  considered  syn- 
chronous. Now  if  it  desired  to  measure  the  length  of  a 
bar  which  is  moving  parallel  to  the  scale  with  which  the 
measurement  is  to  be  made,  it  is  necessary  to  note  the 
positions  of  the  two  ends  of  the  bar  at  the  same  instant. 


378  A  CENTURY  OF  SCIENCE 

So  even  the  measurement  of  the  length  of  a  moving  body 
depends  upon  the  condition  of  synchronism  at  different 
points  in  space. 

The  principle  of  relativity  requires  that  the  velocity 
of  light  shall  be  the  same  in  one  system  as  in  another 
relative  to  which  the  first  is  in  motion.  Hence  the 
definition  of  synchronism  makes  it  possible  to  obtain  a 
set  of  transformations  connecting  space  and  time  meas- 
urement on  one  system  with  those  on  another.  This 
group  of  transformations  is  exactly  that  which  Lorentz 
had  found  would  transform  the  electrodjoiamic  equations 
into  themselves.  But  Einstein's  point  of  view  brought 
out  a  remarkable  reciprocity  which  Lorentz  had  missed. 
If  two  parallel  rods  MN  and  OP  are  in  motion  relative  to 
each  other  in  the  direction  of  their  lengths,  not  only  does 
OP  appear  shortened  to  an  observer  at  rest  with  respect 
to  MN,  but  MN  appears  shorter  than  normal  in  the 
same  ratio  to  an  observer  who  is  moving  along  with  the 
rod  OP.  ^ 

Einstein's  theory  makes  the  velocity  of  light  the  maxi- 
mum speed  with  which  a  signal  can  be  transmitted.  This 
leads  to  his  celebrated  addition  theorem.  Consider  three 
observers  A,  B  and  C.  Let  B  be  moving  relative  to  A 
with  a  velocity  of  nine-tenths  the  velocity  of  light,  and  0 
in  the  same  direction  with  an  equal  velocity  relative  to  B. 
In  terms  of  old-fashioned  notions  of  time  and  space,  the 
velocity  of  C  relative  to  A  would  be  computed  as  one  and 
eight-tenths  the  velocity  of  light.  But  the  relativity 
theory  gives  it  as  ninety-nine  hundredths  the  velocity  of 
light.  For  the  velocity  of  light  can  never  be  surpassed 
by  that  of  any  material  object.  This  deduction  from 
theory  is  most  strikingly  confirmed  by  the  fact  that 
although  beta  particles  have  been  observed  with  velocities 
as  high  as  ninety-nine  hundredths  that  of  light,  the 
velocity  of  light  is  never  quite  equalled.  It  may  be 
remarked  in  passing  that  the  principle  of  relativity 
requires  that  the  masses  of  all  material  bodies  shall  vary 
with  the  velocity  in  the  same  manner  as  Lorentz  found 
to  be  the  case  for  the  electromagnetic  mass  of  the  def orm- 
able  electron.  In  this  connection  Bumstead  (26,  498, 
1908)  has  devised  an  elegant  method  of  deducing  the 
ratio  of  longitudinal  to  transverse  mass. 


A  CENTURY'S  PROGRESS  IN  PHYSICS     379 

The  close  connection  between  electrodynamics  and  the 
principle  of  relativity  is  obvious  from  the  fact  that  both 
lead  to  the  same  time  and  space  transformations.  Fur- 
thermore L.  Page  (37,  169,  1914)  has  shown  that  the 
electrodynamic  equations  can  be  derived  exactly  and  in 
their  entirety  from  nothing  more  than  the  kinematics  of 
relativity  and  the  assumption  that  every  element  of 
charge  is  a  center  of  uniformly  diverging  lines  of  force. 
Hence  it  may  safely  be  asserted  that  no  purely  electro- 
magnetic phenomenon  can  ever  come  into  contradiction 
with  this  principle.  The  simplicity  thus  introduced  into 
the  solution  of  a  certain  class  of  problems  is  enormous. 
As  an  example  consider  the  question  as  to  whether  a  mov- 
ing star  is  retarded  by  the  reaction  of  its  own  radiation. 
This  purely  electrodynamical  problem  is  of  such  com- 
plexity that  attempts  to  solve  it  have  led  to  some  contro- 
versy among  mathematical  physicists.  The  principle  of 
relativity  tells  us  without  recourse  to  analysis  that  no 
retardation  can  exist. 

Throughout  the  nineteenth  century  the  ether  has 
played  a  fundamental  part  in  all  important  physical 
theories  of  light  and  electromagnetism.  But  if  it  is  not 
possible  for  experiment  to  detect  even  the  state  of 
motion  of  the  ether,  why  postulate  the  existence  of  such  a 
medium?  If  it  does  not  possess  the  most  fundamental 
characteristic  of  matter,  how  can  it  possess  such  derived 
properties  as  density  and  elasticity, — properties  which 
any  conceivable  mechanical  medium  must  have  in  order 
to  transmit  transverse  vibrations'?  The  relativist  does 
not  deny  the  existence  of  an  ether.  To  him  the  question 
has  no  more  meaning  than  if  he  were  asked  to  express  an 
opinion  as  to  the  reality  of  parallels  of  latitude  on  the 
earth's  surface.  As  a  convenient  medium  of  expression 
in  describing  certain  phenomena  the  ether  has  justified 
much  of  the  use  which  has  been  made  of  it.  But  to 
attribute  to  it  a  degree  of  substantiality  for  which  there 
is  no  warrant  in  experiment,  is  to  change  it  from  an  aid 
into  an  obstacle  to  the  progress  of  science.  From  the 
relativist  point  of  view  the  distinction  is  very  sharp 
between  those  motions  of  charged  particles  which  are 
experimentally  observable,  and  such  geometrical  conven- 
tions as  electromagnetic  fields,  or  analytical  symbols  as 


380  A  CENTURY  OF  SCIENCE 

electric  and  magnetic  intensities.  These  modes  of  repre- 
sentation liave  T3een  and  still  are  of  the  greatest  use  and 
importance,  but  their  value  in  scientific  description  must 
not  lead  to  lack  of  appreciation  of  their  purely  specula- 
tive character. 

Finally  attention  must  be  drawn  to  the  fact  that  the 
discoveries  of  inductive  science,  embodied  in  the  great 
generalization  we  have  just  been  discussing,  have  led  to 
a  more  intimate  knowledge  of  the  nature  of  time  and 
space  than  twenty  centuries  of  introspection  on  the  part 
of  professional  philosophers.  Minskowski,  whose  prom- 
ise of  greater  achievement  was  cut  off  by  an  untimely 
death,  has  shown  that  four  dimensional  geometry  makes 
possible  the  representation  with  beautiful  simplicity  of 
the  time  and  space  relationships  of  this  theory.  The 
one  time  and  three  space  dimensions  merge  in  such  a 
manner  as  to  form  a  single  whole  with  not  a  vestige  of 
ditferentiation  between  these  fundamental  quantities. 
Wilson  and  Lewis^*'^  have  made  this  representation  famil- 
iar to  American  readers  through  their  admirable  trans- 
lation of  Minskowski 's  work  into  the  notation  of  Gibbs's 
vector  analysis. 

Aberration,  the  Doppler  effect,  anomalous  dispersion, 
— indeed  all  known  phenomena, — are  found  to  be  in 
accord  with  the  principle  of  relativity.  It  must  be 
borne  in  mind,  however,  that  this  principle  applies  only 
to  systems  moving  relative  to  one  another  in  straight 
lines  with  constant  velocities.  That  there  is  something 
absolute  about  rotation  has  been  recognized  since  Fou- 
cault  performed  his  famous  pendulum  experiment  in  1851. 
This  experiment  (C.  S.  Lyman,  12,  251  and  398,  1851) 
consisted  in  setting  a  pendulum  composed  of  a  heavy 
brass  ball  suspended  by  a  long  wire  into  oscillation  in 
such  a  way  as  to  avoid  appreciable  ellipticity  in  its 
motion.  Observation  of  the  rate  at  which  the  ground 
rotates  relative  to  the  plane  of  vibration  of  the  pendulum 
furnished  a  method  of  measuring  the  rotation  of  the 
earth  about  its  axis  without  reference  to  celestial  bodies. 
The  gyroscopic  compass  in  use  to-day  provides  yet 
another  terrestrial  method  of  detecting  this  rotation. 

The  Future  of  Physics. — At  times  during  the  history 
of  physics  it  has  seemed  as  if  the  fundamental  laws  of 


A  CENTURY'S  PEOGRESS  IN  PHYSICS     381 

this  science  had  been  so  completely  formulated  that 
nothing  remained  to  future  generations  beyond  the 
routine  of  deducing  to  the  full  the  consequences  of  these 
laws,  and  increasing  the  precision  of  the  methods  used 
to  measure  the  constants  appearing  in  them.  That 
Laplace  held  this  view  has  already  been  pointed  out,  and 
Maxwell,  in  his  introductory  lecture  at  the  opening  of  the 
Cavendish  laboratory  in  1871,  said,  **This  characteristic 
of  modern  experiments — that  they  consist  principally  of 
measurements — is  so  prominent,  that  the  opinion  seems 
to  have  gotten  abroad  that  in  a  few  years  all  the  great 
physical  constants  will  have  been  approximately  esti- 
mated, and  that  the  only  occupation  which  will  then  be 
left  to  men  of  science  will  be  to  carry  on  these  measure- 
ments to  another  place  of  decimals/'  That  he  himself 
did  not  entertain  this  view  is  made  evident  by  a  succeed- 
ing paragraph.  **But  we  have  no  right  to  think  thus  of 
the  unsearchable  riches  of  creation,  or  of  the  untried  fer- 
tility of  those  fresh  minds  into  which  these  riches  will 
continue  to  be  poured.  It  may  possibly  be  true  that,  in 
some  of  those  fields  of  discovery  which  lie  open  to  such 
rough  observations  as  can  be  made  without  artificial 
methods,  the  great  explorers  of  former  times  have 
appropriated  most  of  what  is  valuable,  and  that  the 
gleanings  which  remain  are  sought  after  rather  for  their 
abstruseness  than  for  their  intrinsic  worth.  But  the  his- 
tory of  science  shows  that  even  during  that  phase  of  her 
progress  in  which  she  devotes  herself  to  improving  the 
accuracy  of  the  numerical  measurement  of  quantities 
with  which  she  has  long  been  familiar,  she  is  preparing 
the  materials  for  the  subjugation  of  new  regions,  which 
would  have  remained  unknown  if  she  had  been  contented 
with  the  rough  methods  of  her  early  pioneers.  ..." 

That  Maxwell's  forecast  of  the  prospects  of  his  science 
was  no  overestimate  will  be  granted  by  those  who  have 
followed  the  progress  of  physics  during  the  last  twenty 
years.  Yet  the  work  accomplished  in  the  past  appears 
small  compared  to  that  which  is  left  to  the  future.  Many 
of  the  unsolved  problems  are  matters  of  fitting  together 
puzzling  details,  but  there  is  at  least  one  whose  solution 
appears  to  demand  a  radical  modification  in  our  funda- 
mental physical  conceptions.     This  is  the  formulation  of 

34 


382  A  CENTURY  OF  SCIENCE 

the  laws  which  govern  the  motions  of  electrons  and  pos- 
itively charged  particles  inside  the  atom. 

Black  Radiation. — The  significance  of  the  problem  was 
first  brought  to  light  through  the  study  of  black  radia- 
tion. By  a  black  body  is  meant  one  whose  distinguishing 
characteristic  is  that  it  emits  and  absorbs  radiation  of  all 
frequencies,  and  black  radiation  is  that  which  will  exist  in 
thermal  equilibrium  with  such  a  body.  The  interest  of 
this  type  of  radiation  lies  in  the  fact,  demonstrated  by 
Kirchhoff,  that  its  nature  depends  only  upon  the  temper- 
ature of  the  black  body  with  which  it  is  in  equilibrium, 
and  on  none  of  this  body's  physical  or  chemical  charac- 
teristics. Thus  we  may  speak  of  the  ** temperature"  of 
the  radiation  itself,  meaning  by  this  the  temperature  of 
the  material  body  with  which  it  would  be  in  equilibrium. 

The  problem  of  black  radiation  is  to  find  the  distribu- 
tion of  energy  among  the  waves  of  different  frequencies 
at  any  given  temperature.  The  first  step  toward  a  solu- 
tion was  made  when  Stefan  showed  experimentally,  and 
Boltzmann  as  a  deduction  from  thermodynamics  and 
electrodynamics,  that  the  total  energy  density  summed 
up  over  all  wave  lengths  varies  with  the  fourth  power  of 
the  absolute  temperature.  If  the  energy  density  is 
plotted  as  ordinate  against  the  wave  length  as  abscissa, 
the  experimental  curve  for  any  one  temperature  rises 
from  the  axis  of  abscissas  at  the  origin,  reaches  a  maxi- 
mum, and  falls  to  zero  again  as  the  wave  length  becomes 
infinitely  great.  Now  Wien's  displacement  law,  the 
second  important  step  toward  the  determination  of  the 
form  of  this  curve,  shows  that  as  the  temperature  is 
raised  the  wave  length  to  which  its  highest  point  cor- 
responds becomes  shorter, — in  fact  this  particular  wave 
length  varies  inversely  with  the  absolute  temperature. 
This  theoretical  conclusion  is  entirely  confirmed  by 
experiment.     (J.  W.  Draper,  4,  388,  1847.) 

Farther  than  this  general  thermodynamical  princi- 
ples are  unable  to  go.  Statistical  mechanics,  however, 
asserts  that  when  a  large  number  of  like  elements  are  in 
thermal  equilibrium,  the  average  kinetic  energy  asso- 
ciated with  each  degree  of  freedom  is  equal  to  a  universal 
constant  multiplied  by  the  absolute  temperature.  This 
*' principle  of  equi-partition  of  energy''  has  been  applied 


A  CENTURY'S  PROGRESS  IN  PHYSICS     383 

in  various  ways  to  obtain  a  radiation  law.  The  most 
straightforward  method  is  based  on  the  equilibrium 
which  must  ensue  between  radiation  field  and  material 
oscillators  when  the  latter  emit,  on  the  average,  as  much 
energy  as  they  absorb.  From  whatever  aspect  the  prob- 
lem is  treated,  however,  the  radiation  law  obtained  from 
the  application  of  the  equi-partition  principle  is  the  same. 
And  while  this  law  agrees  well  with  the  experimental 
curve  for  long  wave  lengths,  it  shows  an  energy  density 
that  becomes  indefinitely  great  for  extremely  short 
waves,  which  is  not  only  at  variance  with  the  facts,  but 
actually  leads  to  an  infinite  value  of  this  quantity  when 
integrated  over  the  entire  spectrum. 

The  Energy  Quantum. — Now  the  principle  of  equi- 
partition  of  energy  rests  securely  on  most  general 
dynamical  principles.  That  these  dynamical  laws  are 
inexact  to  any  such  extent  as  the  divergence  between 
theory  and  experiment  would  indicate,  is  inconceivable; 
that  they  are  insufficient  when  applied  to  motions  of  elec- 
trons in  such  intense  fields  as  occur  within  the  atom 
seems  no  longer  open  to  doubt.  In  order  to  obtain  a 
radiation  formula  in  accord  with  experiment  Planck  has 
found  it  necessary  to  extend  the  atomic  idea  to  energy, 
which  he  conceives  to  exist  in  multiples  of  a  fundamental 
quantum  hv,  v  being  the  frequency  and  h  Planck's  con- 
stant. That  some  such  hypothesis  of  discontinuity  is 
essential  in  order  to  obtain  any  law  that  will  even 
approximately  fit  the  experimental  facts  has  been  proved 
by  Poincare.  But  the  precise  spot  at  which  the  quantum 
is  introduced  differs  for  every  new  derivation  of  Planck's 
law.  As  deduced  most  recently  by  Planck  himself,  the 
quantum  shows  itself  in  connection  with  the  emission  of 
energy  by  the  material  oscillators  with  which  the  radi- 
ation field  is  in  equilibrium.  These  oscillators  are  sup- 
posed to  act  quite  normally  in  every  respect  except 
emission;  here  the  radiation  demanded  by  the  electro- 
dynamic  equations  is  cast  aside,  and  an  oscillator  is 
supposed  to  emit  at  once  all  its  energy  after  it  has  accu- 
mulated an  amount  equal  to  some  integral  multiple  of  hv.) 
A  form  of  the  theory  which  does  not  contain  this  improb- 
able contradiction  of  the  firmly  established  facts  of 
electrodynamics  introduces  the  quantum  into  the  specifi-1 


384  A  CENTURY  OF  SCIENCE 

cation  of  the  energy  of  vibration  which  is  permitted  to 
each  oscillator.  Here  both  emission  and  absorption  fol- 
low the  classical  theory,  but  the  motion  of  an  emitting 
and  absorbing  linear  oscillator  of  frequency  v  is  supposed 
to  be  stable  only  for  those  amplitudes  for  which  the  energy 
of  its  oscillations  is  an  integral  multiple  of  hv.  In  order 
to  maintain  the  energy  at  these  particular  values,  the 
oscillator  may  draw  energy  from,  or  deposit  surplus 
energy  with,  other  degrees  of  freedom  which  partake 
neither  in  emission  nor  absorption,  but  act  merely  as 
storehouses. 

Photoelectric  Effect. — When  investigating  the  produc- 
tion of  electromagnetic  waves,  Hertz  had  noticed  that  a 
spark  passed  more  readily  between  the  terminals  of  his 
oscillator  when  the  negative  electrode  was  illuminated  by 
light  from  another  spark.  Further  investigation  by 
Hallwachs,  Elster  and  Geitel,  and  others  showed  that  this 
effect  was  due  to  the  emission  of  electrons  by  a  metal 
exposed  to  the  influence  of  ultra-violet  light.  Lenard 
discovered  that  the  energy  with  which  a  negatively 
charged  particle  is  ejected  is  entirely  independent  of  the 
intensity  of  the  light,  and  further  investigation  showed 
it  to  depend  only  on  the  frequency.  Einstein  suggested 
that  the  electrons  appearing  in  this  so-called  photo-elec- 
tric effect  start  from  within  the  metal  with  an  initial 
energy  hv.  In  passing  through  the  surface  a  resistance 
is  encountered,  however,  so  he  concluded  that  the  energy 
with  which  the  fastest  moving  electrons  appear  outside 
the  metal  should  be  equal  to  hv  less  the  work  done  in 
overcoming  this  resistance.  Recent  experiments  not 
only  confirm  this  relation,  but  provide  a  most  satisfac- 
tory method  of  determining  the  value  of  h.  Millikan^* 
finds  it  to  be  6-57 (10)"^^  ergs  sec,  which  gives  the  quan- 
tum for  yellow  light  a  value  sixty  times  as  great  as  the 
heat  energy  of  a  monatomic  gas  molecule  at  0°C.  That 
this  large  amount  of  energy  can  be  transferred  from  the 
incident  light  to  the  ejected  electron  is  quite  out  of  the 
question;  it  must  come  from  within  the  atom.  In  this 
way  some  indication  is  obtained  of  how  vast  intra-atomic 
energies  must  be. 

Structure  of  the  Atom. — The  generally  accepted  model 
of  the  atom  is  that  due  chiefly  to  Rutherford.^ ^     He  con« 


A  CENTURY ^S  PROGRESS  IN  PHYSICS     385 

siders  it  to  be  constituted  of  electrons  revolving  about  a 
positive  nucleus  either  singly  or  grouped  in  concentric 
rings,  in  much  the  same  manner  as  the  planets  revolve 
around  the  sun.  Experiments  on  the  scattering  of  alpha 
rays,  however,  show  that  the  nucleus,  while  it  must  have 
a  positive  charge  sufficient  to  neutralize  the  charges  of 
all  the  electrons  moving  around  it,  cannot  have  a  volume 
of  an  order  of  magnitude  greater  than  that  of  the  elec- 
tron. The  number  of  unit  charges  residing  on  it,  except 
in  the  case  of  hydrogen,  which  is  supposed  to  consist  of  a 
singly  charged  nucleus  and  only  one  electron,  is  found  to 
be  approximately  half  the  atomic  weight.  Thus  helium, 
with  an  atomic  weight  of  about  four,  has  a  doubly 
charged  nucleus  with  two  electrons  revolving  about  it, 
and  lithium  a  triply  charged  nucleus  and  three  electrons. 
The  number  of  unit  charges  on  the  nucleus  is  supposed  to 
correspond  with  the  atomic  number  used  by  Moseley  in 
interpreting  the  results  of  his  experiment  on  the  X-ray 
spectra  of  the  elements. 

Now  the  electron  which  is  revolving  around  the  posi- 
tive nucleus  of  a  hydrogen  atom,  must,  according  to  elec- 
trodynamic  laws,  radiate  energy.  This  radiation  will 
act  as  a  resistance  to  its  motion,  causing  its  orbit  to 
become  smaller  and  its  frequency  to  increase.  Hence 
luminous  hydrogen  would  be  expected  to  give  off  a  con- 
tinuous spectrum.  The  very  fine  lines  actually  found 
seem  inexplicable  on  the  classical  dynamical  and  electro- 
dynamical  theories.  These  lines,  and  those  of  many 
other  spectra,  may  even  be  grouped  into  series,  and  the 
relations  between  them  expressed  in  mathematical  form. 
Formulae  have  been  proposed  by  Balmer,  Rydberg,  Ritz 
and  others,  all  of  which  contain  a  universal  constant  N 
as  well  as  certain  parameters  which  must  be  varied  by 
unity  in  passing  from  one  line  of  a  series  to  the  next. 

In  1913  Bohr^s  proposed  anatomic  theory  which  brings 
to^  light  a  remarkable  numerical  relationship  between 
this  quantity  N  and  Planck's  constant  h.  He  postulated 
that  the  electron  in  the  hydrogen  atom,  for  instance,  can- 
not revolve  in  a  circle  of  any  arbitrary  radius,  but  is  con- 
fined to  those  orbits  for  which  its  kinetic  energy  is  an 
integral  multiple  of  -|  h  n,  n  being  its  orbital  frequency. 
Now  at  times  this  electron  is  supposed  to  jump  from  an 


386  A  CENTURY  OF  SCIENCE 

outer  to  an  inner  orbit,  when  the  excess  energy  of  the  first 
orbit  over  the  second  is  radiated  away.  But  the  energy 
emitted  is  also  taken  to  be  equal  to  hv,  where  v  is  the  fre- 
quency of  the  radiation.  Hence  v  can  be  determined,  and 
the  expression  obtained  for  it  is  exactly  that  given  long 
before  by  Balmer  as  an  empirical  law.  The  most 
remarkable  thing  about  it,  however,  is  that  Bohr's  result 
contains  a  constant  involving  h  and  the  electronic  charge 
and  mass  which  has  precisely  the  value  of  the  universal 
constant  N  of  Balmer 's  and  Rydberg's  formulae.  In  all, 
the  theory  accounts  for  three  series  of  hydrogen,  and 
yields  satisfactory  results  for  helium  atoms  which  have 
lost  an  electron,  or  lithium  atoms  which  have  a  double 
positive  charge.  But  for  atoms  which  retain  more  than 
a  single  electron  it  seems  no  longer  to  hold. 

The  three  mentioned  are  only  the  most  clearly  defined 
of  a  growing  group  of  phenomena  in  which  the  quantum 
manifests  itself.  Its  significance  and  the  alteration  in 
our  fundamental  conceptions  to  w^hich  it  seems  to  be 
leading  is  for  the  future  to  make  clear.  That  it  presents 
the  most  important  and  interesting  problem  as  yet 
unsolved  few  physicists  would  deny. 

American  Physicists. — In  attempting  to  cover  the 
progress  of  physics  during  the  last  hundred  years  in  the 
space  of  a  few  pages,  many  important  developments  of 
the  subject  have  of  necessity  remained  untouched,  and 
the  treatment  of  many  others  has  been  entirely  inade- 
quate. Among  those  appearing  in  the  Journal  of  which 
no  mention  has  been  made  are  LeConte's  (25,  62,  1858) 
discovery  of  the  sensitive  flame  and  Rood's  (46,  173, 
1893)  invention  of  the  flicker  photometer.  However, 
enough  has  been  recounted  to  indicate  the  pre-eminent 
position  in  the  history  of  physics  in  America  occupied  by 
four  men:  Joseph  Henry,  of  the  Albany  Academy, 
Princeton,  and  the  Smithsonian  Institution;  Henry 
Augustus  Rowland,  of  Johns  Hopkins  University; 
Josiah  Willard  Gibbs,  of  Yale;  and  Albert  Abraham 
Michelson,  of  the  United  States  Naval  Academy,  Case 
School  of  Applied  Science,  Clark  University,  and  the 
University  of  Chicago.  Of  these,  the  last  named  has  the 
distinction  of  being  the  only  American  physicist  to  have 
received  the  Nobel  prize,  though  there  is  little  doubt  that 


A  CENTURY'S  PROGRESS  IN  PHYSICS     387 

the  other  three  would  have  been  similarly  honored  had 
not  their  important  work  been  published  prior  to  the 
institution  of  this  award.  All  four  occupy  high  places 
in  the  ranks  of  the  world's  great  men  of  science,  and  the 
investigations  carried  out  by  them  and  their  fellow 
workers  in  America  have  given  to  their  country  a  posi- 
tion in  the  annals  of  physics  which  is  by  no  means  insig- 
nificant. 

The  JournaVs  Part  in  Meteorology, 

The  meteorological  investigations  published  in  the 
early  numbers  of  the  Journal  have  played  an  important 
role  in  establishing  a  correct  theory  of  storms.  Before 
the  origin  of  the  United  States  Signal  Service  in  1871  no 
systematic  weather  reports  were  issued  by  any  govern- 
mental agency  in  this  country,  and  consequently  the  work 
of  collecting  as  well  as  interpreting  meteorological  data 
rested  entirely  in  the  hands  of  interested  individuals  and 
institutions.  The  earliest  important  studies  of  storms 
to  appear  in  the  Journal  were  contributed  by  Redfield  of 
New  York,  whose  first  paper  (20,  17,  1831)  treated  in 
considerable  detail  a  violent  storm  which  passed  over 
Long  Island,  Connecticut  and  Massachusetts  in  1821. 
He  concluded  that  **the  direction  of  the  wind  at  a  partic- 
ular place,  forms  no  part  of  the  essential  character  of  a 
storm,  but  is  only  incidental  to  that  particular  portion 
...  of  the  track  of  the  storm  which  may  chance  to 
become  the  point  of  observation,  .  .  .  the  direction  of 
the  wind  being,  in  all  cases,  compounded  of  both  the  rota- 
tive and  progressive  velocities  of  the  storm.'*  A  few 
years  later,  analvses  of  twelve  ^*  gales  and  hurricanes  of 
the  Western  Atlantic"  (31,115, 1837)  led  to  the  statenient 
that  the  phenomena  involved  **are  to  be  ascribed  mainly 
to  the  mechanical  gravitation  of  the  atmosphere,  as  con- 
nected with  the  rotative  and  orbital  movements  of  the 
earth's  surface."  In  this  paper  is  emphasized  the  fact 
that  the  wind  may  blow  in  diametrically  opposite  direc- 
tions at  points  near  the  storm  center.  '*  While  one  ves- 
sel has  been  lying-to  in  a  heavy  gale  of  wind,  another,  not 
more  than  thirty  leagues  distant,  has  at  the  very  same 
time  been  in  another  gale  equally  heavy,  and  lying-to 
with  the  wind  in  quite  an  opposite  direction. ' '    From  an 


388  A  CENTURY  OF  SCIENCE 

accompanying  sketch  showing  wind  directions,  the  reader 
would  infer  that,  at  this  time,  Redfield  believed  the 
motion  of  the  air  to  be  very  nearly  in  circles  about  the 
storm  center.  The  same  idea  is  conveyed  by  a  later 
paper  (42,  112, 1842).  Espy  (39,  120,  1840)  of  Philadel- 
phia, however,  claimed  that  observation  showed  rather 
that  the  wind  blew  inwards  toward  a  central  point,  if  the 
storm  were  round  in  shape,  or  toward  a  central  line,  if 
it  were  oblong.  This  view  Redfield  (42,  112,  1842)  con- 
tested, and  brought  forth  much  evidence  to  prove  its 
falsity.  A  later  statement  (1,  1, 1846)  of  his  own  theory 
is  as  follows:  '*I  have  never  been  able  to  conceive,  that 
the  wind  in  violent  storms  moves  only  in  circles.  On  the 
contrary,  a  vortical  movement  .  .  .  appears  to  be  an 
essential  element  of  their  violent  and  long  continued 
action,  of  their  increased  energy  towards  the  center  or 
axis,  and  of  the  accompanying  rain.  .  .  .  The  degree  of 
vorticular  inclination  in  violent  storms  must  be  subject, 
locally,  to  great  variations;  but  it  is  not  probable  that, 
on  an  average  of  the  different  sides,  it  ever  comes  near  to 
forty-five  degrees  from  the  tangent  of  a  circle, — and 
that  such  average  inclination  ever  exceeds  two  points  of 
the  compass,  may  well  be  doubted.^'  A  qualitative 
explanation  of  the  effect  of  the  earth's  rotation  on  the 
direction  of  the  wind  near  the  storm  center  had  already 
been  given  by  Tracy  (45,  65, 1843),  and  this  was  followed 
some  years  later  by  FerrePs  (31,  27, 1861)  very  thorough 
quantitative  investigation  of  the  dynamics  of  the 
atmosphere. 

A  number  of  individuals  kept  systematic  records  of 
meteorological  observations,  among  whom  was  Loomis, 
whose  storm  analyses  did  much  to  settle  the  merits  of  the 
rival  theories  of  Redfield  and  Espy.  In  studying  the 
storm  of  1836  (40,  34,  1841)  he  had  drawn  on  the  map 
lines  through  those  points  in  the  track  of  the  storm  where 
the  barometer,  at  any  given  hour,  is  lowest.  While  this 
method  revealed  the  general  direction  in  which  the  storm 
was  progressing,  it  failed  to  give  much  indication  of  its 
size  or  shape.  In  discussing  the  two  tornadoes  of  Feb- 
ruary, 1842,  one  of  which  had  already  been  described 
in  the  Journal  (43,  278,  1842),  he  adopted  a  new  and 
more  illuminating  graphical  method.    Instead  of  connect- 


A  CENTURY'S  PROGRESS  IN  PHYSICS    389 

ing  points  of  lowest  pressure,  he  drew  a  curve  through  all 
points  where  the  barometer  stood  at  its  normal  level,  then 
one  through  those  points  at  which  the  pressure  was  2/10 
of  an  inch  below  normal,  and  so  on.  Temperature  he 
treated  in  much  the  same  way,  and  the  strength  and 
direction  of  the  wind  were  indicated  by  arrows.  This 
innovation  gave  to  his  storm  analyses  a  significance 
which  had  been  entirely  lacking  in  those  of  his  predeces- 
sors, and  led  to  the  familiar  systems  of  isobars  and  iso- 
therms in  use  on  the  daily  charts  issued  by  the  Weather 
Bureau  at  the  present  time.  Loomis  advocated  careful 
observations  for  one  year  at  stations  50  miles  apart  all 
over  the  United  States,  so  that  sufficient  data  might  be 
obtained  to  settle  once  for  all  the  law  of  storms.  His 
efforts,  seconded  by  those  of  Henry,  Bache,  Pierce,  Abbe, 
and  Lapham,  led  eventually  to  the  establishment  of  the 
Signal  Service,  and  the  publication  of  daily  weather 
maps  according  to  the  plan  advocated  thirty  years 
before.  These  maps  afforded  a  basis  for  further 
analyses  of  storms,  which  he  published  in  numerous 
*^ Contributions  to  Meteorology''  (8,  1,  1874,  et  seq.) 
between  1874  and  his  death  in  1890. 

In  addition  to  his  work  on  storms,  Loomis  made  a  care- 
ful study  of  the  earth's  magnetism  (34,  290, 1838  et  seq.), 
and  of  the  aurora  borealis  (28,  385,  1859  et  seq.).  That 
a  connection  existed  between  sunspots,  aurora,  and  ter- 
restrial magnetism  was  already  recognized.  Loomis  (50, 
153,  1870  et  seq.),  however,  showed  that  the  periodicity 
of  the  aurora  borealis,  as  well  as  of  excessive  disturb- 
ances in  the  earth's  magnetic  field,  corresponds  very 
closely  with  that  of  sunspots. 

Kotes, 

» J.  W.  Gibbs,  Trans.  Conn.  Acad.  Arts  and  Sci.,  3,  108  and  343.     Abstract 
by  the  author,  the  Journal,  16,  441,  1878. 
^  H.  K.  Onnes,  Nature,  93,  481,  1914. 
"  H.  Hertz,  Wied.  Ann.,  34,  551,  1888  et  seq. 
*E.  F.  Nichols  and  G.  F.  Hull,  Phys.  Eev.,  13,  307,  1901  et  seq. 
»J.  J.  Thomson,  PhU.  Mag.,  44,  293,  1897. 

•  R.  A.  Millikan,  Phys.  Eev.,  2,  109,  1913. 
'  P.  Zeeman,  Phil.  Mag.,  43,  226,  1897. 

«  H.  A.  Lorentz,  Phil.  Mag.,  43,  232,  1897. 

•  S.  J.  Barnett,  Phys.  Rev.,  6,  239,  1915,  and  10,  7,  1917. 
^^  W.  C.  Rontgen,  Wied.  Ann.,  64,  1,  1898  et  seq. 


390  A  CENTURY  OF  SCIENCE 

"W.  Friedrieh,  P.  Knipping,  and  M.  Laue,  Ann.  d.  Phys.,  41,  971,  1913. 
^  H.  G.  J.  Moseley,  Phil.  Mag.,  26,  1024,  1913,  and  27,  703,  1914. 
"  E.  W.  Morley  and  D.  C.  MiUer,  Phil.  Mag.,  9,  680,  1905. 
"17,  891,  1905. 

"  E.  B.  Wilson  and  G.  N.  Lewis,  Proe.  Am.  Acad,  of  Arts  and  Sci.,  48, 
389,  1912. 

"  R.  A.  Millikan,  Phys.  Rev.,  7,  355,  1916. 
"  E.  Rutherford,  Phil.  Mag.,  21,  669,  1911. 
"  N.  Bohr,  Phil.  Mag.,  26,  1,  1913  et  seq. 


XII 

A  CENTURY  OF  ZOOLOGY  IN  AMERICA 

By  WESLEY  R.  COE 

THIS  article  is  intended  as  a  brief  survey  of  the 
development  of  zoology  in  America,  and  no  attempt 
is  made  to  give  a  general  history  of  the  science. 
There  are  numerous  accounts  in  several  languages  of 
zoological  history  in  general,  among  them  being  W.  A. 
Locy^s  *^ Biology  and  its  Makers.''  Brief  outlines  of  the 
history  of  zoology  may  be  found  in  many  zoological  and 
biological  text-books. 

For  the  history  of  American  zoology  the  reader  is 
referred  to  Packard's  report  on  **A  Century's  Progress 
in  American  Zoology,"  published  in  the  American  Nat- 
uralist, (10,  591,  1876),  to  Packard's  *^ History  of  Zool- 
ogy," published  in  volume  1  of  the  Standard  Natural 
History  (pp.  Ixii  to  Ixxii,  1885) ;  to  G.  B.  Goode's 
** Beginnings  of  Natural  History  in  America,"^  and 
** Beginnings  of  American  Science,"^  and  to  H.  S.  Pratt's 
Manual  of  the  Common  Invertebrate  Animals  (pp.  1-9), 
1916.  In  Binney's  **  Terrestrial  Air-breathing  MoUusks 
of  the  United  States"  (1851)  is  a  chapter  on  the  rise  of 
scientific  zoology  in  the  IJnited  States  which  well  describes 
the  zoological  conditions  in  the  early  part  of  the  century, 
while  numerous  monographs  and  papers  give  the  history 
of  the  investigations  on  the  various  groups  of  animals 
or  on  special  fields  of  study. 

Brief  biographical  sketches  of  the  most  distinguished 
of  our  older  Naturalists — Wilson,  Audubon,  Agassiz, 
"Wyman,  Gray,  Dana,  Baird,  Marsh,  Cope,  Goode  and 
Brooks  are  given  in  **  Leading  American  Men  of  Sci- 
ence," edited  by  David  Starr  Jordan,  1910.  More  exten- 
sive biographies  have  been  published  separately,  and^  the 
activities  of  a  number  of  the  more  prominent  American 


392  A  CENTUEY  OF  SCIENCE 

zoologists    have    been    recorded    in    the    Biographical 
Memoirs  of  the  National  Academy  of  Sciences. 

The  developmental  history  of  zoology  in  America  falls 
naturally  into  four  fairly  well  marked  periods,  namely : — • 
1,  Period  of  descriptive  natural  history,  previous  to 
1847,  embracing  the  early  studies  on  the  classification 
and  habits  of  animals,  characteristic  of  the  zoological 
work  previous  to  the  arrival  of  Louis  Agassiz  in  Amer- 
ica. 2,  Period  of  morphology  and  embryology,  1847- 
1870,  during  which  the  influence  of  Agassiz  directed  the 
zoological  studies  toward  problems  concerning  the  rela- 
tionships of  animals  as  indicated  by  their  structure  and 
developmental  history.  3,  Period  of  evolution,  1870- 
1890,  when  the  principle  of  natural  selection  received 
general  recognition  and  the  zoological  studies  were 
largely  devoted  to  the  applications  of  the  theory  to 
all  groups  of  animals.  4,  Period  of  experimental  biol- 
ogy, since  1890,  during  which  time  have  occurred  the 
remarkable  advances  in  our  knowledge  of  the  nature  of 
organisms  through  the  application  of  experimental 
methods  in  the  various  branches  of  the  modern  science  of 
biology. 

American  Zoology  in  1818, 

At  the  beginning  of  the  century  which  this  volume 
commemorates,  the  accumulated  biological  knowledge  of 
the  world  consisted  mainly  of  what  is  to-day  called 
descriptive  natural  history.  The  zoological  treatises  of 
the  time  were  devoted  to  the  names,  distinguishing  char- 
acters and  habits  of  the  species  of  animals  and  plants 
known  to  the  naturalists  of  Europe  either  as  native 
species  or  as  the  results  of  explorations  in  other  parts 
of  the  world.  This  required  little  more  than  a  super- 
ficial knowledge  of  their  general  anatomical  structures. 

The  naturalists  of  those  days  had  no  conception  of  the 
life  within  the  cell  which  we  now  know  to  form  the  basis 
of  all  the  activities  of  animals  and  plants,  nor  had  they 
even  the  necessary  means  of  studying  such  life.  The 
compound  microscope,  so  necessary  for  the  study  of  even 
the  largest  of  the  cells  of  the  body,  was  not  adapted  to 
such  use  until  1835,  although  the  instrument  was  invented 
in  the  seventeenth  century.  With  the  perfection  of  the 
microscope  came  a  period  of  enthusiastic  study  of  micro- 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     393 

scopic  organisms  and  microscopic  structures  of  higher 
animals  and  plants.  It  was  not  until  twenty  years  after 
the  founding  of  the  Journal  that  the  cell  theory  of  struc- 
ture and  function  in  all  organisms  was  established  by  the 
discoveries  of  Schleiden  and  Schwann. 

The  beginning  of  the  nineteenth  century  saw  great 
zoological  activity  in  Europe,  and  particularly  in  France. 
Buff  on 's  great  work  on  the  Natural  History  of  Animals 
had  recently  been  completed,  Cuvier  had  only  one  year 
before  published  his  classic  work  in  comparative  anat- 
omy, **Le  Regno  Animal,''  and  Lamarck's  *  *  Philosophie 
Zoologique"  had  then  aroused  a  new  interest  in  classi- 
fication and  comparative  anatomy  from  an  evolutionary 
standpoint.  E.  Geoffroy  St.-Hilaire  was  at  the  same 
time  supporting  an  evolutionary  theory  based  on  embry- 
onic influences  resulting  in  sudden  modifications  of  adult 
structure.  These  epoch-making  discoveries  and  theories 
gained  a  considerable  following  in  France,  Germany  and 
England,  but  seem  to  have  had  little  influence  on  the 
zoological  work  of  the  following  half  century  in  America. 

The  science  of  zoology  as  understood  to-day  is  com- 
monly said  to  have  been  founded  by  Linnaeus  by  the 
publication  of  the  modern  system  of  classification  in  the 
tenth  edition  of  his  *^Systema  Naturae"  in  1758.  The 
influence  of  Linnaeus  aroused  an  interest  in  biological 
studies  throughout  Europe  and  stimulated  new  investi- 
gations in  all  groups  of  organisms.  Such  studies  as 
related  to  animals  naturally  followed  first  the  classifica- 
tion and  relationship  of  species,  that  is,  systematic 
zoology,  and  then  led  gradually  into  the  development  of 
the  different  branches  of  the  subject,  as  morphology, 
comparative  anatomy,  physiology,  and  embryology, 
which  eventually  were  recognized  as  almost  independent 
sciences. 

Of  these  sciences  systematic  zoology,  which  has  come 
to  mean  the  classification,  structure,  relationship,  distri- 
bution and  habits,  or  natural  history,  is  the  pioneer  in  any 
region.  Thus  we  find  in  our  new  country  at  the  time  of 
the  founding  of  the  Journal  in  1818,  only  sixty  years 
after  the  publication  of  Linnaeus'  great  work,  the  begin- 
ning of  American  zoology  taking  the  form  of  the  collec- 
tion and  description  of  our  native  animals. 


394  A  CENTUEY  OF  SCIENCE 

It  is  true  that  many  of  our  more  conspicuous  and  easily 
collected  animals  were  described  long  before  the  opening 
of  the  nineteenth  century,  but  this  is  to  be  credited  mainly 
to  the  work  of  European  naturalists  who  had  made  expedi- 
tions to  this  country  for  the  purpose  of  studying  and 
collecting.  These  collections  were  then  taken  to  Europe 
and  the  results  published  there.  We  thus  find  in  the  12th 
edition  of  Linnaeus  descriptions  of  over  500  American 
species,  about  half  of  which  were  birds.  As  an  illustra- 
tion of  the  extent  to  which  some  of  these  works  covered 
the  field  even  in  those  early  days  may  be  mentioned  a 
monograph  in  two  quarto  volumes  with  many  beautifully 
colored  plates  on  the  '  *  Natural  History  of  the  rarer  Lepi- 
dopterous  Insects  of  Georgia."  This  was  published  in 
London  in  1797  by  J.  E.  Smith  from  the  notes  and  draw- 
ings of  John  Abbot,  one  of  the  keenest  naturalists  of 
any  period. 

During  the  early  years  of  the  nineteenth  century,  how- 
ever, economic  conditions  in  our  country  became  such  as  to 
give  opportunity  for  scientific  thought.  Educated  men 
then  formed  themselves  into  societies  for  the  discussion  of 
scientific  matters.  This  naturally  led  to  the  establish- 
ment of  publications  whereby  the  papers  presented  to  the 
societies  could  be  published  and  made  available  to  the 
advancement  of  science  generally.  The  most  influential 
of  these  was  the  Journal  of  the  Philadelphia  Academy  of 
Natural  Science,  which  was  established  in  1817,  and  was 
devoted  largely  to  zoological  papers.  The  Annals  of  the 
New  York  Lyceum  of  Natural  History  date  from  1823, 
and  the  Journal  of  the  Boston  Society  of  Natural  History 
from  1834.  The  Transactions  of  the  American  Philo- 
sophical Society  in  Philadelphia  and  the  Memoirs  of  the 
American  Academy  of  Arts  and  Sciences  in  Boston  also 
published  many  zoological  articles. 

In  these  publications  and  in  the  Journal,  which  was 
founded  in  1818,  appear  the  descriptions  of  newly  dis- 
covered animal  species,  with  observations  on  their  habits. 

The,  number  of  investigators  in  this  field  in  the  first 
quarter  of  the  nineteenth  century  was  but  few,  and  most 
of  these  were  compelled  to  take  for  the  work  such  time 
as  they  could  spare  from  their  various  occupations. 

Gradually  the  workers  became  more  numerous  untU 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     395 

about  the  middle  of  the  century  zoology  was  taught  in  all 
the  larger  colleges.  The  science  thereby  developed  into 
a  profession. 

For  some  years  the  studies  remained  largely  of  a  sys- 
tematic nature,  and  embraced  all  groups  of  animals,  but 
long  before  the  close  of  the  century  the  attention  of  the 
majority  of  the  ever  increasing  group  of  zoologists  was 
directed  into  more  promising  channels  for  research  and 
there  came  the  development  of  the  sciences  of  compara- 
tive anatomy,  physiology,  embryology,  experimental 
zoology,  cytology,  genetics,  and  the  like,  while  the  sys- 
tematists  became  specialists  in  the  various  animal  groups. 

But  the  work  in  systematic  zoology  remains  incomplete 
and  many  native  species  are  still  undescribed  or  imper- 
fectly classified.  It  is  perhaps  fortunate  that  a  few 
faithful  systematists  remain  at  their  tasks  and  tend  to 
keep  the  experimentalists  from  the  disaster  which  might 
otherwise  result  from  the  confusion  of  the  species  under 
investigation. 

Period  of  Descriptive  Xatural  History,— Previous  to  184:7 • 

Of  the  few  American  naturalists  whose  writings  were 
published  toward  the  end  of  the  eighteenth  century  and 
at  the  beginning  of  the  nineteenth  the  names  of  William 
Bartram  (1739-1823),  Benjamin  Barton  (1766-1815), 
Samuel  Mitchill  (1764-1831),  William  Peck  (1763-1822), 
and  Thomas  Jefferson  (1743-1826),  require  special  men- 
tion. Bartram  ^s  entertaining  volume  describing  his 
travels  through  the  Carolinas,  Georgia  and  Florida,  pub- 
lished in  1793,  contains  a  most  interesting  account  of  the 
birds  and  other  animals  which  he  found. 

Barton  wrote  many  charming  essays  on  the  natural 
history  of  animals,  but  was  more  particularly  interested 
in  botany.  MitchilPs  most  important  works  include  a 
history  of  the  fishes  of  New  York  (1814),  and  additions  to 
an  edition  of  Bewick's  General  History  of  Quadrupeds. 
The  latter,  published  in  1804,  contains  descriptions  and 
figures  of  some  American  species  and  is  the  first  Ameri- 
can work  on  mammals. 

Peck  has  the  distinction  of  writing  the  first  paper  on 
systematic  zoology  published  in  America.  This  was  a 
description  of  new  species  of  fishes  and  was  printed  in 


396  A  CENTURY  OF  SCIENCE 

1794.  He  is  also  well  known  for  his  work  on  insects 
and  fungi. 

Jefferson  in  1781  published  an  interesting  book 
describing  the  natural  history  of  Virginia,  and  during 
his  presidency  was  of  inestimable  service  to  zoology 
through  his  support  of  scientific  expeditions  to  the  west- 
ern portions  of  the  country. 

Previous  to  Agassiz's  introduction  of  laboratory  meth- 
ods of  study  in  comparative  anatomy  and  embryology  in 
1847,  American  naturalists  generally  confined  their  atten- 
tion to  the  study  of  the  classification  and  habits  of  the 
multitude  of  undescribed  animals  and  plants  of  the 
region. 

Such  studies  were  naturally  begun  on  the  larger  and 
more  generally  interesting  animals  such  as  the  birds  and 
mammals,  and  although  many  of  these  were  fairly  well 
described  as  to  species  before  the  opening  of  the  nineteenth 
century,  little  was  known  of  their  habits.  The  natural 
history  of  our  eastern  birds  first  became  well  known 
through  the  accurate  illustrations  and  exquisitely  written 
descriptions  of  Alexander  Wilson  (in  1808-1813).  Bona- 
parte's continuation  of  Wilson's  work  was  published  in 
four  folio  volumes  beginning  in  1826. 

In  1828  appeared  the  first  of  Audubon's  magnificent 
folio  illustrations  of  our  birds.  These  were  published  in 
England,  with  later  editions  of  smaller  plates  in  America. 
NuttalPs  Manual  of  the  Ornithology  of  the  United  States 
appeared  in  1832-1834. 

The  second  work  on  American  mammals  appeared  in 
the  second  American  edition  of  Guthrie's  Geography, 
published  in  1815.  The  author  is  supposed  to  have  been 
George  Ord,  although  his  name  does  not  appear.  In  1825 
Harlan  published  his  *^ Fauna  Americana:  Descriptions 
of  the  Mammiferous  Animals  inhabiting  North  Amer- 
ica." This  was  largely  a  compilation  from  European 
writers,  particularly  from  Demarest's  Mammalogie,  and 
had  little  value. 

In  1826  Amos  Eaton  published  a  small  *^  Zoological 
Text-book  comprising  Cuvier's  four  grand  divisions 
of  Animals:  also  Shaw's  improved  Linnean  genera, 
arranged  according  to  the  classes  and  orders  of  Cuvier 
and  Latreille.     Short  descriptions  of  some  of  the  most 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     397 

common  species  are  given  for  students'  exercises.  Pre- 
pared for  Rensselaer  school  and  the  popular  class-room." 
*^Four  hundred  and  sixty-one  genera  are  described  in 
this  text-book.  They  embrace  every  known  species  of 
the  Animal  Kingdom.''  This  is  a  compilation  from 
European  sources  with  a  few  American  species  of  various 
groups  included.  On  the  other  hand,  Godman's  Natural 
History,  in  three  volumes  (1826-1828),  was  an  illustrated 
and  creditable  work.  Such  was  also  the  case  with  Sir 
John  Richardson's  Fauna  Boreali  Americana  of  which 
the  volume  on  quadrupeds  was  published  in  England  in 
1829.  The  other  volumes  on  birds,  fishes  and  insects 
appeared  between  1827  and  1836.  Audubon  and  Bach- 
man's  beautifully  illustrated  ^^  Quadrupeds  of  North 
America"  was  issued  between  1841  and  1850. 

About  1840  several  of  the  states  inaugurated  natural 
history  surveys  and  published  catalogues  of  the  local 
faunas.  The  reports  on  the  animals  of  Massachusetts 
and  New  York  are  the  most  complete  zoological  mono- 
graphs published  in  America  up  to  that  time.  This  is 
particularly  true  of  DeKay's  Natural  History  of  New 
York  published  between  1842  and  1844  in  beautifully 
illustrated  quarto  volumes. 

The  leader  in  the  systematic  studies  in  the  early  part 
of  the  century  was  Thomas  Say,  who  published  descrip- 
tions of  a  large  number  of  new  species  of  animals,  par- 
ticularly reptiles,  mollusks,  Crustacea  and  insects.  Say's 
conchology,  printed  in  1816  in  Nicholson's  Cyclopedia, 
is  the  first  American  work  of  its  kind.  This  was 
reprinted  in  1819  under  the  title  **Land  and  Fresh-water 
Shells  of  the  United  States."  In  1824-1828  appeared 
the  three  volumes  of  Say's  American  Entomology. 

The  proniinent  position  held  by  Say  in  the  zoological 
work  of  this  period  is  illustrated  by  the  following  para- 
graph from  Eaton's  Zoological  Text-book  (1826,p.l33) : 
**At  present  but  a  small  proportion  of  American  Ani- 
mals, excepting  those  of  large  size,  have  been  sought  out 
.  .  .  And  though  Mr.  Say  is  doing  much ;  without  assist- 
ance, his  life  must  be  protracted  to  a  very  advanced 
period  to  afford  him  time  to  complete  the  work.  But  if 
every  student  will  contribute  his  mite,  by  sending  Mr. 
Say  duplicates  of  all  undescribed  species,  we  shall  prob- 

25 


398  A  CENTURY  OF  SCIENCE 

ably  be  in  possession  of  a  system,  very  nearly  complete, 
in  a  few  years.''  How  different  is  the  attitude  of  the 
zoologist  of  to-day  who  sees  the  goal  much  further  away 
after  a  century's  progress  through  the  industry  of  hun- 
dreds of  investigators. 

During  the  period  of  Say's  most  active  work  he  is 
reported  to  have  **  slept  in  the  hall  of  the  Philadelphia 
Academy  of  Natural  Sciences,  where  he  made  his  bed 
beneath  the  skeleton  of  a  horse  and  fed  himself  on  bread 
and  milk." 

Next  to  Say,  the  most  active  zoologist  of  the  early  part 
of  the  century  was  Charles  Alexander  Lesueur,  who 
described  and  beautifully  illustrated  many  new  species  of 
fishes,  reptiles,  and  marine  invertebrates.  A  memoir  by 
George  Ord,  published  in  this  Journal  (8,  189,  1849), 
gives  a  full  list  of  Lesueur 's  papers. 

One  of  the  most  prolific  writers  of  the  period  was  Con- 
stantine  Rafinesque,  a  man  of  great  brilliancy  but  one 
whose  imagination  so  often  dominated  his  observations 
that  many  of  his  descriptions  of  plants  and  animals  are 
wholly  unreliable. 

United  States  Exploring  Expedition. — In  1838  a  fortu- 
nate circumstance  occurred  which  eventually  brought 
American  systematic  zoology  into  the  front  ranks  of  the 
science.  This  opportunity  was  offered  by  the  United 
States  Exploring  Expedition  under  the  command  of 
Admiral  Wilkes.  With  James  D.  Dana  as  naturalist,  the 
expedition  visited  Madeira,  Cape  Verde  Islands,  eastern 
and  western  coasts  of  South  America,  Polynesia,  Samoa, 
Australia,  New  Zealand,  Fiji,  Hawaiian  Islands,  west 
coast  of  United  States,  Philippines,  Singapore,  Cape  of 
Good  Hope,  etc. 

Of  the  extensive  collections  made  on  this  four-years' 
cruise,  Dana  had  devoted  particular  attention  to  the 
study  of  the  corals  and  allied  animals  (Zoophytes)  and  to 
the  Crustacea.  In  1846  the  report  on  the  Zoophytes  was 
published  in  elegant  folio  form  with  colored  plates. 
Six  years  later  the  first  volume  of  the  report  on  Crus- 
tacea appeared,  with  a  second  volume  after  two 
additional  years  (1854).  These  reports  describe  and 
beautifully  illustrate  hundreds  of  new  species,  and 
include  the  first  comprehensive  studies  of  the  animals 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     399 

forming  well-known  corals.  They  remain  as  the  most 
conspicuous  monuments  in  American  invertebrate  zool- 
ogy. Unfortunately  the  very  limited  edition  makes  them 
accessible  in  only  a  few  large  libraries.  The  other, 
equally  magnificent,  volumes  include:  Mollusca  and 
Shells,  by  A.  A.  Gould,  1856;  Herpetology,  by  Charles 
Girard,  1858;  Mammalogy  and  Ornithology,  by  John 
Cassin,  1858.^ 

Principal  investigators. — Of  the  many  writers  on  ani- 
mals at  this  period  of  descriptive  natural  history,  the  fol- 
lowing were  prominent  in  their  special  fields  of  study : 

Ayres,  Lesueur,  Mitchill,  Storer,  Linsley,  Wyman, 
DeKay,  Smith,  Kirtland,  Rafinesque  and  Haldeman 
described  the  fishes. 

Green,  Barton,  Harlan,  Le  Conte,  Say,  and  especially 
Holbrook,  studied  the  reptiles  and  amphibia.  Holbrook's 
great  monograph  of  the  reptiles  (North  American  Her- 
petology) was  published  between  1834  and  1845. 

Wilson,  Audubon,  Nuttall,  Cooper,  DeKay,  Brewer, 
Ord,  Baird,  Gould,  Bachman,  Linsley  and  Fox  were 
among  the  numerous  writers  on  birds. 

Godman,  Ord,  Richardson,  Audubon,  Bachman,  De- 
Kay, Linsley  and  Harlan  published  accounts  of  mam- 
mals. 

On  the  invertebrates  an  important  general  work  enti- 
tled **Invertebrata  of  Massachusetts;  Mollusca,  Crus- 
tacea, Annelida  and  Radiata''  was  published  by  A.  A. 
Gould  in  1841,  which  contains  all  the  New  England 
species  of  these  groups  known  to  that  date. 

Lea,  Totten,  Adams,  Barnes,  Gould,  Binney,  Conrad, 
Hildreth,  Haldeman,  were  the  principal  writers  on  mol- 
lusks.  The  Crustacea  were  studied  by  Say,  Gould,  Halde- 
man, Dana;  the  insects  by  Say,  Melsheimer,  Peck, 
Harris,  Kirby,  Herrick ;  the  spiders  by  Hentz ;  the  worms 
by  Lee ;  the  coelenterates  and  echinoderms  by  Say,  Man- 
tell  and  others. 

''  The  history  of  entomology  in  the  United  States  pre- 
vious to  1846  is  given  by  John  G.  Morris  in  the  Journal 
XI  17,  1846).  In  this  article  F.  Y.  Melsheimer  is  stated 
to  be  the  father  of  American  Entomology,  while  Say  was 
the  most  prolific  writer.  Say's  entomological  papers, 
edited  by  J.  L.  Le  Conte,  were  completely  reprinted  with 


400  A  CENTUEY  OF  SCIENCE 

their  colored  illustrations  in  1859.  The  first  economic 
treatise  is  that  by  Harris  on  Insects  Injurious  to  Vege- 
tation*, printed  in  1841.     This  has  had  many  editions. 

Zoology  in  the  American  Journal  of  Science, 
1818-1846. 

The  establishment  of  the  Journal  gave  a  further  impe- 
tus to  the  scientific  activities  of  Americans  in  furnishing 
a  convenient  means  for  publishing  the  results  of  their 
work.  In  the  first  volume  of  the  Journal,  for  example, 
are  two  zoological  articles  by  Say  and  a  dozen  short 
articles  on  various  topics  by  Rafinesque,  the  latter  being 
curious  combinations  of  facts  and  fancy.  Most  of  the 
zoological  papers  appearing  in  its  first  series  of  50  vol- 
umes are  characteristic  of  an  undeveloped  science  in  an 
undeveloped  country.  They  deal,  naturally,  with  obser- 
vational studies  on  the  structure  and  classification  of 
species  discovered  in  a  virgin  field,  with  notes  on  habits 
and  life  histories. 

Many  of  the  papers  are  purely  systematic  and  include 
the  first  descriptions  of  numerous  species  of  our  mol- 
lusks,  Crustacea,  insects,  vertebrates  and  other  groups. 
Of  these,  the  writings  of  C.  B.  Adams,  Barnes,  A.  A. 
Gould  and  Totten  on  mollusks,  of  J.  D.  Dana  on  corals 
and  Crustacea,  of  Harris  on  insects,  of  Harlan  on  reptiles, 
and  of  Jeffries  Wyman  and  D.  Humphreys  Storer  on 
fishes  are  representative  and  important. 

The  progress  of  zoology  in  America  during  the  first 
twenty-eight  years  of  the  Journal's  existence,  that  is,  up 
to  the  year  1846,  is  thus  summarized  by  Professor  Silli- 
man  in  the  preface  to  vol.  50  (page  ix),  1847 : 

*'Our  zoolo^  has  been  more  fully  investigated  than  our 
mineralogy  and  botany;  but  neither  department  is  in  danger 
of  being  exhausted.  The  interesting  travels  of  Lewis  and  Clark 
have  recently  brought  to  our  knowledge  several  plants  and 
animals  before  unknown.  Foreign  naturalists  are  frequently 
visiting  our  territory ;  and,  for  the  most  part,  convey  to  Europe 
the  fruits  of  their  researches,  while  but  a  small  part  of  our 
own  is  examined  and  described  by  Americans:  certainly  this 
is  little  to  our  credit  and  still  less  to  our  advantage.  Honorable 
exceptions  to  the  truth  of  this  remark  are  furnished  by  the 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     401 

exertions  of  some  gentlemen  in  our  principal  cities,  and  in 
various  other  parts  of  the  Union."' 

During  these  28  years  the  Journal  had  been  of  great 
service  to  zoology  not  only  in  the  publication  of  the 
results  of  investigations  but  also  in  the  review  of  import- 
ant zoological  publications  in  Europe  as  well  as  in 
America.  There  were  also  the  reports  of  meetings  of 
scientific  societies.  In  fact  all  matters  of  zoological 
interest  were  brought  to  the  attention  of  the  JournaPs 
readers. 

The  Influence  of  Louis  Agassiz, 

At  the  time  of  the  founding  of  the  Journal  and  for 
nearly  thirty  years  thereafter  descriptive  natural  his- 
tory constituted  practically  the  entire  work  of  American 
zoologists.  In  this  respect  American  science  was  far 
behind  that  in  Europe  and  particularly  in  France.  It 
was  not  until  the  fortunate  circumstances  which  brought 
the  Swiss  naturalist,  Louis  Agassiz,  to  our  country  in 
1846  that  the  modern  conceptions  of  biological  science 
"were  established  in  America. 

Agassiz  was  then  39  years  of  age  and  had  already 
absorbed  the  spirit  of  generalization  in  comparative 
anatomy  which  dominated  the  work  of  the  great  leaders 
in  Europe,  and  particularly  in  Paris.  The  influence  of 
Leuckart,  Tiedemann,  Braun,  Cuvier  and  Von  Humboldt 
directed  Agassiz 's  great  ability  to  similar  investigations, 
and  he  was  rapidly  coming  into  prominence  in  the  study 
of  modern  and  fossil  fishes  when  the  opportunity  to  con- 
tinue his  research  in  America  was  presented.  On  arriv- 
ing on  our  shores  the  young  zoologist  was  so  inspired 
with  the  opportunities  for  his  studies  in  the  new  country 
that  he  decided  to  remain. 

Bringing  with  him  the  broad  conceptions  of  his  dis- 
tinguished European  masters,  he  naturally  founded  a 
similar  school  of  zoology  in  America.  It  is  from  this 
beginning  that  the  present  science  of  zoology  with  its 
many  branches  has  developed. 

It  must  be  remembered  in  this  connection  that  the  great 
service  which  Agassiz  rendered  to  American  zoology  con- 
sisted mainly  in  making  available  to  students  in  America 
the  ideals  and  methods  of  European  zoologists.     This  he 


402  A  CENTUEY  OF  SCIENCE 

was  eminently  fitted  to  do  both  because  of  his  European 
training  and  because  of  his  natural  ability  as  an  inspir- 
ing leader. 

The  times  in  America,  moreover,  were  fully  ripe  for 
the  advent  of  European  culture.  There  were  already  in 
existence  natural  history  societies  in  many  of  our  cities 
and  college  communities.  These  societies  not  only  held 
meetings  for  the  discussion  of  biological  topics,  but 
established  museums  open  to  the  public,  and  to  which  the 
public  was  invited  to  contribute  both  funds  and  speci- 
mens. This  led  to  a  wide  popular  interest  in  natural  his- 
tory. It  was  therefore  comparatively  easy  for  such  a 
man  as  Agassiz  to  develop  this  favorable  public  attitude 
into  genuine  enthusiasm. 

The  American  Journal  of  Science  announces  the 
expected  visit  of  Agassiz  as  a  most  promising  event  for 
American  Zoology  (1,  451, 1846) :  ^^His  devotion,  ability, 
and  zeal — ^his  high  and  deserved  reputation  and  ...  his 
amiable  and  conciliating  character,  will,  without  doubt, 
secure  for  him  the  cordial  cooperation  of  our  naturalists 
.  .  .  nor  do  we  entertain  a  doubt  that  we  shall  be  liberally 
repaid  by  his  able  review  and  exploration  of  our 
country.''  We  of  to-day  can  realize  how  abundantly  this 
prophecy  was  fulfilled. 

In  the  succeeding  volume  (2,  440,  1846)  occurs  the 
record  of  Agassiz 's  arrival.  **We  learn  with  pleasure 
that  he  will  spend  several  years  among  us,  in  order 
thoroughly  to  understand  our  natural  history. ' ' 

Immediately  on  reaching  Boston,  Agassiz  began  the 
publication  of  articles  on  our  fauna,  and  the  following 
year  he  was  appointed  to  a  professorship  at  Harvard. 
The  Journal  says  (4,  449, 1847) :  ** Every  scientific  man  in 
America  will  be  rejoiced  to  hear  so  unexpected  a  piece  of 
good  news.''  The  next  year  the  Journal  (5,  139,  1848) 
records  Agassiz 's  lecture  courses  at  New  York  and 
Charleston,  his  popularity  with  all  classes  of  the  people 
and  the  gift  of  a  silver  case  containing  $250  in  half  eagles 
from  the  students  of  the  College  of  Physicians  and 
Surgeons. 

The  service  of  Agassiz  to  American  zoology,  therefore, 
consisted  not  only  in  the  publication  of  the  results  of  his 
researches  and  his  philosophical  considerations  there- 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     403 

from,  but  also,  and  perhaps  in  even  greater  degree,  in  the 
popularization  of  science.  In  the  latter  direction  were 
his  inspiring  lectures  before  popular  audiences  and  the 
early  publication  of  a  zoological  text-book.  This  book, 
published  in  1848,  was  entitled  ^^  Principles  of  Zoology, 
touching  the  Structure,  Development,  Distribution  and 
Natural  arrangement  of  the  races  of  Animals,  living  and 
extinct,  with  numerous  illustrations. ' '  It  was  written 
with  the  cooperation  of  Augustus  A.  Gould.  The  review 
of  this  book  in  the  Journal  (6,  151, 1848)  indicates  clearly 
the  broad  modern  principles  underlying  the  new  era 
which  was  beginning  for  American  zoology. 

*'A  work  emanating  from  so  high  a  source  as  the  Principles 
of  Zoology,  hardly  requires  commendation  to  give  it  currency. 
The  public  have  become  acquainted  with  the  eminent  abilities 
of  Prof.  Agassiz  through  his  lectures,  and  are  aware  of  his 
vast  learning,  wide  reach  of  mind,  and  popular  mode  of  illus- 
trating scientific  subjects  .  .  .  The  volume  is  prepared  for 
the  student  in  zoological  science;  it  is  simple  and  elementary 
in  style,  full  in  its  illustrations,  comprehensive  in  its  range,  yet 
well  considered  and  brought  into  the  narrow  compass  requisite 
for  the  purpose  intended. '* 

The  titles  of  its  chapters  will  show  how  little  it  differs 
in  general  subject  matter  from  the  most  recent  text-book 
in  biology.  Chapter  I,  The  Sphere  and  fundamental 
principles  of  Zoology;  II,  General  Properties  of  Organ- 
ized Bodies ;  III,  Organs  and  Functions  of  Animal  Life ; 
IV,  Of  Intelligence  and  Instinct;  V,  Of  Motion  (appa- 
ratus and  modes) ;  VI,  Of  Nutrition;  VII,  Of  the  Blood 
and  Circulation ;  VIII,  Of  Respiration ;  IX,  Of  the  Secre- 
tions ;  X,  Embryology  (Egg  and  its  Development) ; 
XI,  Peculiar  Modes  of  Reproduction;  XII,  Meta- 
morphoses of  Animals ;  XIII,  Geographical  Distribution 
of  Animals ;  XIV,  Geological  Succession  of  Animals,  or 
their  Distribution  in  Time. 

A  moment's  consideration  of  the  fact  that  all  these 
topics  are  excellently  treated  will  show  how  great  had 
been  the  progress  of  zoology  in  the  first  half  of  the  nine- 
teenth century.  The  sixty  years  that  have  elapsed  since 
the  publication  of  this  book  have  served  principally  to 
develop  these  separate  lines  of  biology  into  special  fields 
of  science  without  reorganization  of  the  essential  princi- 


404  A  CENTURY  OF  SCIENCE 

pies  here  recognized.  This  remained  for  many  years 
the  standard  zoological  and  physiological  text-book,  and 
was  republished  in  several  editions  here  and  in  England. 
Another  popular  book  is  entitled  ^*  Methods  of  Study  in 
Natural  History'^  (1864). 

More  than  400  books  and  papers  were  written  by 
Agassiz,  over  a  third  of  which  were  published  before 
he  came  to  America.  They  cover  both  zoological  and 
geological  topics,  including  systematic  papers  on  living 
and  fossil  groups  of  animals,  but  most  important  of  all 
are  his  philosophical  essays  on  the  general  principles  of 
biology. 

One  of  Agassiz 's  greatest  services  to  zoology  was  the 
publication  of  his  ^ ^ Bibliographia  Zoologise  et  Geologise" 
by  the  Ray  Society,  beginning  with  1848.  The  publica- 
tion of  the  Lowell  lectures  in  Comparative  Embryology 
in  1849  gave  wide  audience  to  the  general  principles  now 
recognized  in  the  biogenetic  law  of  ancestral  remin- 
iscence. As  stated  in  the  Journal  (8,  157,  1849),  the 
*^  object  of  the  Lectures  is  to  demonstrate  that  a  natural 
method  of  classifying  the  animal  kingdom  may  be 
attained  by  a  comparison  of  the  changes  which  are  passed 
through  by  different  animals  in  the  course  of  their  devel- 
opment from  the  egg  to  the  perfect  state;  the  change 
they  undergo  being  considered  as  a  scale  to  appreciate 
the  relative  position  of  the  species."  These  ** principles 
of  classification"  are  fully  elucidated  in  a  separate  pam- 
phlet, and  are  discussed  at  length  in  the  Journal  (11, 
122, 1851). 

One  of  the  most  interesting  of  Agassiz 's  numerous 
philosophical  essays,  originally  contributed  to  the  Jour- 
nal (9,  369,  1850),  discusses  the  *' Natural  Relations 
between  Animals  and  the  elements  in  which  they  live." 
Another  philosophical  paper  contributed  to  the  Journal 
discusses  the  **  Primitive  diversity  and  number  of  Ani- 
mals in  Geological  times"  (17,  309,  1854).  Of  his  sys- 
tematic papers,  those  on  the  fishes  of  the  Tennessee  river, 
describing  many  new  species,  were  published  in  the  Jour- 
nal (17,  297,  353, 1854). 

Agassiz 's  beautifully  illustrated  ^*  Contributions  to  the 
Natural  History  of  the  United  States"  cover  many  sub- 
jects in  morphology  and  embryology,  which  are  treated 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     405 

with  STich  thoroughness  and  breadth  of  view  as  to  give 
them  a  place  among  the  zoological  classics.  The  Essay 
on  Classification,  the  North  American  Testudinata,  the 
Embryology  of  the  turtle,  and  the  Acalephs  are  the 
special  topics.  These  are  summarized  and  discussed  at 
length  in  the  Journal  (25,  126,  202,  321,  342,  1858;  30, 
142,1860;  31,295,1861). 

The  volume  on  the  **  Journey  in  Brazil"  (1868)  in  joint 
authorship  with  Mrs.  Agassiz  is  a  fascinating  narrative 
of  exploration. 

The  conceptions  which  Agassiz  held  as  to  the  most 
essential  aim  of  zoological  study  are  well  illustrated 
in  his  autobiographical  sketch,  where  he  writes  :^ 

''I  did  not  then  know  how  much  more  important  it  is  to  the 
naturalist  to  understand  the  structure  of  a  few  animals,  than 
to  command  the  whole  field  of  scientific  nomenclature.  Since  I 
have  become  a  teacher,  and  have  watched  the  progress  of  stu- 
dents, I  have  seen  that  they  all  begin  in  the  same  way;  but 
how  many  have  grown  old  in  the  pursuit,  without  ever  rising 
to  any  higher  conception  of  the  study  of  nature,  spending  their 
life  in  the  determination  of  species,  and  in  extending  scientific 
terminology ! '  * 

It  is  not  surprising,  then,  that  under  such  influence  the 
older  systematic  studies  should  be  replaced  in  large 
measure  by  those  of  a  morphological  and  embryological 
nature. 

The  personal  influence  of  Agassiz  is  still  felt  in  the 
lives  of  even  the  younger  zoologists  of  the  present  day. 
For  the  investigators  of  the  present  generation  are  for 
the  most  part  indebted  to  one  or  another  of  Agassiz 's 
pupils  for  their  guidance  in  zoological  studies.  These 
pupils  include  his  son  Alexander  Agassiz,  Allen,  Brooks, 
Clarke,  Fewkes,  Goode,  Hyatt,  Jordan,  Lyman,  Morse, 
Packard,  Scudder,  Verrill,  Wilder,  and  others — ^leaders 
in  zoological  work  during  the  last  third  of  the  nineteenth 
century.  Through  such  men  as  these  the  inspiration  of 
Agassiz  has  been  handed  on  in  turn  to  their  pupils  and 
from  them  to  the  younger  generation  of  zoologists. 

The  essential  difference  between  the  work  of  Agassiz 
and  that  of  the  American  zoologists  who  preceded  him 
was  in  his  power  of  broad  generalizations.     To  him  the 


406  A  CENTURY  OF  SCIENCE 

organism  meant  a  living  witness  of  some  great  natural 
law,  in  the  interpretation  of  which  zoology  was  engaged. 
The  organism  in  its  structure,  in  its  development,  in  its 
habits  furnished  links  in  the  chain  of  evidence  which, 
when  completed,  would  reveal  the  meaning  of  nature.  Of 
all  Agassiz's  pupils,  probably  William  K.  Brooks  most 
fittingly  perpetuated  his  master 's  ideals. 

Period  of  Morphology  and  Embryology ,    1847-1870, 

The  new  aspect  of  zoology  which  came  as  a  result  of 
the  influence  of  Agassiz  characterized  the  zoological  work 
of  the  fifties  and  sixties,  that  is,  until  the  significance 
of  the  natural  selection  theory  of  Darwin  and  Wallace 
became  generally  appreciated. 

The  work  in  these  years  and  well  into  the  seventies  was 
largely  influenced  by  the  morphological,  embryological 
and  systematic  studies  of  Louis  Agassiz  and  his  school. 
The  structure,  development,  and  homologies  of  animals 
as  indicating  their  relationship  and  position  in  the 
scheme  of  classification  was  prominent  in  the  work  of 
this  period.  The  adaptations  of  animals  to  their  envi- 
ronment and  the  application  of  the  biogenetic  law  to  the 
various  groups  of  animals  were  also  favorite  subjects 
of  study. 

The  most  successful  investigators  in  this  period  on  the 
different  groups  of  animals  include: — Louis  Agassiz  on 
the  natural  history  and  embryology  of  coelenterates  and 
turtles;  A.  Agassiz,  embryology  of  echinoderms  and 
worms;  H.  J.  Clark,  embryology  of  turtles  and  syste- 
matic papers  on  sponges  and  coelenterates;  E.  Desor, 
echinoderms  and  embryology  of  worms;  C.  Girard, 
embryology,  worms,  and  reptiles;  J.  Leidy,  protozoa, 
coelenterates,  worms,  anatomy  of  mollusks ;  W.  0.  Ayres 
and  T.  Lyman,  natural  history  of  echinoderms ;  McCrady, 
development  of  acalephs ;  W.  Stimpson,  marine  inverte- 
brates ;  A.  E.  Verrill,  coelenterates,  echinoderms,  worms ; 
A.  Hyatt,  evolutionary  theories,  bryozoa  and  mollusks; 
Pourtales,  deep  sea  fauna ;  C.  B.  Adams,  A.  and  W.  G. 
Binney,  Brooks,  Carpenter,  Conrad,  Dall,  Jay,  Lea, 
S.  Smith,  Tryon,  mollusks;  E.  S.  Morse,  brachiopods, 
mollusks ;  J.  I).  Dana,  coelenterates  and  Crustacea ;  Kirt- 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     407 

land,  Loew,  Edwards,  Hagen,  Melsheimer,  Packard, 
Riley,  Scudder,  Walsh,  insects;  Gill,  Holbrook,  Storer, 
fishes;  Cope,  evolutionary  theories,  fishes  and  amphibia; 
Baird,  reptiles  and  birds ;  J.  A.  Allen,  amphibia,  reptiles 
and  birds;  Brewer,  Cassin,  Coues,  Lawrence,  birds; 
Audubon,  Bachman,  Baird,  Cope,  Wilder,  mammals. 

The  progress  of  ornithology  in  the  United  States  pre- 
vious to  1876  is  well  described  in  a  paper  by  J.  A.  Allen  in 
the  American  Naturalist  (10,  536, 1876).  A  sketch  of  the 
early  history  of  conchology  is  given  by  A.  W.  Tryon  in 
the  Journal  (33,  13,1862). 

Jeffries  Wyman  was  the  most  prominent  comparative 
anatomist  of  this  period.  His  work  includes  classic 
papers  on  the  anatomy  and  embryology  of  fishes, 
amphibia,  and  reptiles. 

Zoology  in  the  American  Journal  of  Science, 
184:6-1870. 

The  fifty  volumes  of  the  second  series  of  the  Journal, 
including  the  years  1846  to  1870,  cover  approximately 
this  period  of  morphology  and  embryology.  During  this 
period  the  Journal  occupied  a  very  important  place  in 
zoological  circles,  for  J.  D.  Dana  was  for  most  of  this 
period  the  editor-in-chief,  while  Louis  Agassiz  and  Asa 
Gray  were  connected  with  it  as  associate  editors.  More- 
over, in  1864  one  of  the  most  promising  of  Agassiz 's 
pupils,  Addison  E.  Verrill,  was  called  to  Yale  as  pro- 
fessor of  zoology  and  was  made  an  associate  editor 
in  1869. 

In  the  Journal,  therefore,  may  be  found,  in  its  original 
articles,  together  with  its  reports  of  meetings  and 
addresses  and  its  reviews  of  literature,  a  fairly  complete 
account  of  the  zoological  activity  of  the  period.  The 
most  important  zoological  researches,  both  in  Europe 
and  America,  were  reviewed  in  the  bibliographic  notices. 

The  most  important  series  of  zoological  articles  are  by 
Dana  himself.  As  his  work  on  the  zoophytes  and  Crus- 
tacea of  the  U.  S.  Exploring  Expedition  continued,  he 
published  from  time  to  time  general  summaries  of  his 
conclusions  regarding  the  relationships  of  the  various 
groups.  Included  among  these  papers  are  philosophical 
essays  on  general  biological  principles  which  must  have 


408  A  CENTURY  OF  SCIENCE 

had  mucli  influence  on  the  biological  studies  of  the  time, 
and  which  form  a  basis  for  many  of  our  present  concepts. 
The  importance  of  these  papers  warrants  the  list  being 
given  in  full.  The  titles  are  here  in  many  cases  abbre- 
viated and  the  subjects  consolidated. 

General  views  on  Classification,  1,  286,  1846. 

Zoophytes,  2,  64,  187,  1846 ;  3,  1,  160,  337,  1847. 

Genus  Astraea,  9,  295,  1850. 

Conspectus  crustaceorum,  8,  276,  424,  1849;  9,  129,  1850;  11, 
268,  1851. 

Genera  of  Gammaracea,  8,  135,  1849;  of  Cyclopacea,  1,  225, 
1846. 

Markings  of  Carapax  of  Crabs,  11,  95,  1851. 

Classification  of  Crustacea,  11,  223,  425;  12,  121,  238,  1851; 
13,  119;  14,  297,  1852;  22,  14,  1856. 

Geographical  distribution  of  Crustacea,  18,  314,  1854;  19,  6; 
20,  168,  349,  1855. 

Alternation  of  Generations  in  Plants  and  Radiata,  10,  341, 
1850. 

Parthenogenesis,  24,  399,  1857. 

On  Species,  24,  305,  1857. 

Classification  of  Mammals,  35,  65,  1863 ;  37,  157,  1864. 

Cephalization,  22,  14,  1856 ;  36,  1,  321,  440,  1863 ;  37,  10,  157, 
184,  1864;  41,  163,  1866;  12,  245,  1876. 

Homologies  of  insectean  and  crustacean  types,  36,  233,  1863 ; 
47,  325,  1894. 

Origin  of  life,  41,  389,  1866. 

Relations  of  death  to  life  tu  nature,  34,  316,  1862. 

Of  the  above,  the  articles  on  cephalization  as  a  funda- 
mental principle  in  the  development  of  the  system  of 
animal  life  have  attracted  much  attention.  The  evidence 
from  comparative  anatomy,  paleontology,  and  embry- 
ology alike  supports  the  view  that  advance  in  the 
ontogenetic  as  well  as  in  the  phylogenetic  stages  is  cor- 
related with  the  unequal  growth  of  the  cephalic  region  as 
compared  with  the  rest  of  the  body.  Dana  shows  that 
this  principle  holds  good  for  all  groups  of  animals.  His 
homologies  of  the  limbs  of  arthropods  and  vertebrates, 
however,  do  not  accord  with  more  modern  views. 

Other  papers  on  the  same  and  allied  topics  were  pub- 
lished by  Dana  in  other  periodicals.  His  most  conspicu- 
ous zoological  works,  however,  are  his  reports  on  the 
Zoophytes  and  Crustacea  of  the  United  States  Explor- 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     409 

ing  Expedition,  1837-1842.  The  former  consists  of  741 
quarto  pages  and  61  folio  plates,  describing  over  200  new 
species,  while  the  Crustacea  report,  in  two  volumes,  has 
1620  pages  and  96  folio  plates,  with  descriptions  of  about 
500  new  species.  Each  of  these  remains  to-day  as  the 
most  important  contribution  to  the  classification  of  the 
respective  groups.  The  relationships  of  the  species, 
genera  and  families  were  recognized  with  such  remark- 
able judgment  that  Dana's  admirable  system  of  classifi- 
cation has  remained  the  basis  for  all  subsequent  work. 

Dana's  critical  reviews  (25,  202,  321, 1858)  of  Agassiz's 
**  Contribution  to  the  Natural  History  of  the  United 
States ' '  are  among  the  most  interesting  of  his  philosoph- 
ical discussions  concerning  the  relationships  of  animals 
as  revealed  by  their  structure,  their  embryology,  and 
their  geological  history. 

The  remaining  zoological  articles  in  this  series  cover 
nearly  the  whole  range  of  systematic  zoology.  Espe- 
cially important  are  the  articles  by  Verrill  on  coelenter- 
ates,  echinoderms,  worms  and  other  invertebrates. 

In  the  years  following  the  publication  of  Darwin's 
Origin  of  Species  in  1859  occur  many  articles  on  the 
theory  of  natural  selection.  Some  of  the  writers  attack 
the  theory,  while  others  give  it  more  or  less  enthusiastic 
support. 

Experimental  methods  in  solving  biological  problems 
were  little  used  at  this  time,  although  a  few  articles  of 
this  nature  appear  in  the  Journal.  Of  these,  a  paper  by 
W.  C.  Minor  (35,  35,  1863)  on  natural  and  artificial 
fission  in  some  annelids  has  considerable  interest  to-day. 

Exploring  Expeditions, 

Of  the  important  zoological  expeditions  the  following 
may  be  selected  as  showing  their  influence  on  American 
Zoology : 

The  North  Pacific  Expedition,  with  William  Stimpson 
as  zoologist,  returned  in  1856  with  much  new  information 
concerning  the  marine  life  of  the  coasts  of  Alaska  and 
Japan  and  many  new  species  of  invertebrates. 

In  1867-1869  the  United  States  Coast  Survey  extended 
its  explorations  to  include  the  deep-sea  marine  life  off 


410  A  CENTURY  OF  SCIENCE 

the  southeastern  coasts  and  Gulf  of  Mexico  under  the 
leadership  of  Pourtales  and  Agassiz. 

The  Challenger  explorations  (1872-1876)  added  greatly 
to  the  knowledge  of  marine  life  off  the  American  coast 
as  well  as  in  other  parts  of  the  world. 

The  explorations  of  the  United  States  Fish  Commis- 
sion succeeded  those  of  the  Coast  Survey  in  the  collection 
of  marine  life  off  our  coasts  and  in  our  fresh  waters. 
These  have  continued  since  1872  and  have  yielded  most 
important  results  from  both  the  scientific  and  economic 
standpoints. 

Under  the  charge  of  Alexander  Agassiz  the  Coast  Sur- 
vey Steamer  *^ Blake,"  in  1877  to  1880,  was  engaged  in 
dredging  operations  in  three  cruises  to  various  parts  of 
the  Atlantic.  The  U.  S.  Fish  Commission  Steamer 
**  Albatross,"  also  in  charge  of  Agassiz,  made  three  expe- 
ditions in  the  tropical  and  other  parts  of  the  Pacific  in  the 
years  from  1891  to  1905.  The  study  of  these  collections 
has  added  greatly  to  our  knowledge  of  systematic  zoology 
and  geographical  distribution.  The  reports  on  some  of 
the  groups  are  still  in  course  of  preparation. 

Period  of  Evolution,  1870-1890, 

The  time  from  1870  to  1890  may  be  appropriately  called 
the  period  of  evolution,  for  although  it  commences  eleven 
years  after  the  publication  of  the  Origin  of  Species,  the 
importance  of  the  natural  selection  theory  was  but  slowly 
receiving  general  recognition.  The  hesitation  in  accept- 
ing this  theory  was  due  in  no  small  degree  to  the  opposi- 
tion of  Louis  Agassiz.  After  the  acceptance  of  evolution, 
although  morphological  and  embryological  studies  con- 
tinued as  before,  they  were  prosecuted  with  reference  to 
their  bearing  on  evolutionary  problems. 

Following  closely  the  methods  which  had  produced  so 
much  progress  during  the  life  of  Agassiz,  the  field  of 
zoology  was  now  occupied  by  a  new  generation,  among 
whom  the  pupils  of  Agassiz  were  the  most  prominent. 

The  teaching  of  biology  at  this  time  was  also  strongly 
influenced  by  Huxley,  whose  methods  of  conducting  lab- 
oratory classes  for  elementary  students  were  adopted  in 
most  of  our  large  schools  and  colleges.     This  placed 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     411 

biology  on  the  same  plane  with  chemistry  as  a  means  for 
training  in  laboratory  methods  and  discipline,  with  the 
added  advantage  that  the  subject  of  biology  is  much  more 
intimately  connected  with  the  student's  everyday  life  and 
affairs. 

This  increasing  demand  for  instruction  in  biology  and 
the  consequent  necessity  for  more  teachers  brought  an 
increasing  number  of  investigators  into  this  field. 

Conspicuous  in  this  period  was  the  work  of  E.  D.  Cope, 
best  known  as  a  paleontologist,  but  whose  work  on  the 
classification  of  the  various  groups  of  vertebrates  stands 
preeminent,  and  whose  philosophical  essays  on  evolution 
had  much  influence  on  the  evolutionary  thought  of  the 
time.  He  was  a  staunch  supporter  of  the  Lamarckian 
doctrine.  Alpheus  Hyatt  also  maintained  this  theory, 
and  brought  together  a  great  accumulation  of  facts  in  its 
support.  He  thereby  contributed  largely  to  our  knowl- 
edge of  comparative  anatomy  and  embryology.  A.  S. 
Packard,  whose  publications  cover  a  wide  range  of 
topics,  was  best  known  for  his  text-books  of  zoology  and 
his  manuals  on  insects. 

W.  K.  Brooks  was  a  leading  morphologist  and  embry- 
ologist.  S.  F.  Baird,  for  many  years  the  head  of  the 
United  States  Fish  Commission,  was  the  foremost 
authority  on  fish  and  fisheries  and  is  also  noted  for  his 
work  on  reptiles,  birds  and  mammals.  The  man  of 
greatest  influence,  although  by  no  means  the  greatest 
investigator,  was  C.  0.  Whitman.  It  is  to  him  that  we 
owe  the  inception  of  the  Marine  Biological  Laboratory, 
the  most  potent  influence  in  American  zoology  to-day; 
the  organization  of  the  American  Morphological  Society, 
the  forerunner  of  the  present  American  Society  of  Zoolo- 
gists; and  the  establishment  of  the  Journal  of  Morph- 
ology. G.  B.  Goode  was  distinguished  for  his  work  on 
fishes  and  for  his  writings  on  the  history  of  science. 

E.  L.  Mark,  C.  S.  Minot,  and  Alexander  Agassiz  were 
acknowledged  leaders  in  their  special  fields  of  research — 
Mark  in  invertebrate  morphology  and  embryology,  and 
Minot  in  vertebrate  embryology,  while  Alexander  Agassiz 
made  many  important  discoveries  in  the  systematic 
zoology  and  embryology  of  marine  animals,  and  to  him 


412  A  CENTURY  OF  SCIENCE 

we  owe  in  large  measure  our  knowledge  of  the  life  in  the 
oceans  of  nearly  all  parts  of  the  world. 

The  knowledge  of  the  representatives  of  the  different 
divisions  of  the  American  fauna  had  now  become  suffi- 
cient to  allow  the  publication  of  monographs  on  the  vari- 
ous classes,  orders  and  families.  At  this  time  also  par- 
ticular attention  was  given  to  the  marine  invertebrates 
of  all  groups. 

Of  the  many  investigators  working  on  the  various 
groups  of  animals  at  this  time  only  a  few  may  be  men- 
tioned. The  protozoa  were  studied  by  Leidy,  Clark, 
Ryder,  Stokes ;  the  sponges  by  Clark,  Hyatt ;  the  coelen- 
terates  by  A.  Agassiz,  S.  F.  Clarke,  Verrill ;  the  echino- 
derms  by  A.  Agassiz,  Brooks,  Kingsley,  Fewkes,  Lyman, 
Verrill;  the  various  groups  of  worms  by  Benedict, 
Eisen,  Silliman,  Verrill,  Webster,  Whitman;  the  mol- 
lusks  by  A.  and  W.  G.  Binney,  Tryon,  Conrad,  Dall,  San- 
derson Smith,  Stearns,  Verrill ;  the  Brachiopods  by  Dall 
and  Morse;  the  Bryozoa  by  Hyatt;  the  Crustacea  by 
S.  I.  Smith,  Harger,  Hagen,  Packard,  Kingsley,  Faxon, 
Herrick;  the  insects  by  Packard,  Horn,  Scudder,  C.  H. 
Fernald,  Williston,  Norton,  Walsh,  Fitch,  J.  B.  Smith, 
Comstock,  Howard,  Riley  and  many  others;  spiders  by 
Emerton,  Marx,  McCook ;  tunicates  by  Packard  and  Ver- 
rill; fishes  by  Baird,  Bean,  Cope,  Gilbert,  Gill,  Goode, 
Jordan,  Putnam;  amphibians  and  reptiles  by  Cope; 
birds  by  Baird,  Brewer,  Coues,  Elliott,  Henshaw,  Allen, 
Merriam,  Brewster,  Ridgway;  and  the  mammals  by 
Allen,  Baird,  Cope,  Coues,  Elliott,  Merriam,  Wilder. 

Interest  in  the  evolutionary  theory  continued  to 
increase  and  eventually  developed  into  the  morpholog- 
ical and  embryological  studies  which  reached  their  cul- 
mination between  1885  and  1890  under  the  guidance 
of  Whitman,  Mark,  Minot,  Brooks,  Kingsley,  E.  B.  Wilson 
and  other  famous  zoologists  of  the  time.  In  these  years 
the  Journal  of  Morphology  was  established  and  the 
American  Morphological  Society  was  formed. 

The  morphological,  embryological  and  paleontological 
evidences  of  evolution  as  indicated  by  homologies,  devel- 
opmental stages  and  adaptations  were  the  most  absorb- 
ing subjects  of  zoological  research  and  discussion. 


^^^ 


s.^-^-^^ 


^^^ 


"^^Vf    ' 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     413 


Zoology  in  the  American  Journal  of  Science^ 
1870-1918. 

The  third  series  of  the  Journal  (1870-1895),  likewise 
including  fifty  volumes,  embraces  this  period  of  zoologi- 
cal activity  in  morphological  and  embryological  studies, 
culminating  with  the  inception  of  the  modern  experimen- 
tal methods. 

In  this  period  also  occurred  the  greatest  progress  in 
marine  systematic  zoology,  due  to  the  explorations  of  the 
United  States  Fish  Commission  off  the  Atlantic  Coast. 
The  Journal  had  an  important  share  in  the  zoological 
development  of  this  period  also,  for  A.  E.  Verrill,  who 
was  now  an  associate  editor,  was  in  charge  of  the  collec- 
tions of  marine  invertebrates.  Consequently  most  of  the 
discoveries  in  this  field  were  published  in  the  Journal  in 
numerous  original  contributions  by  Verrill  and  his  asso- 
ciates. The  explorations  of  the  U.  S.  Fish  Commission 
Steamer  **  Albatross '*  are  described  from  year  to  year  by 
Verrill,  with  descriptions  of  the  new  species  of  inverte- 
brates discovered. 

The  numerous  original  contributions  by  Verrill  on 
subjects  of  general  zoological  interest  as  well  as  on  those 
of  a  systematic  nature  give  this  third  series  of  the  Jour- 
nal much  zoological  importance.  VerrilPs  papers  cover 
almost  the  whole  field  of  descriptive  zoology,  but  are 
mainly  devoted  to  marine  invertebrates.  Those  which 
were  originally  contributed  to  the  Journal  or  summarized 
by  him  in  his  literature  reviews  include  the  following 
topics : 

Sponges,  16,  406,  1878. 

Coelenterates,  37,  450,  1864;  44,  125,  1867;  45,  411,  186,  46, 
143,  1868;  47,  282,  1869;  48,  116,  419,  1869;  49,  370,  1870;  3, 
187,  432,  1872;  6,  68,  1873;  21,  508,  1881;  6,  493,  1898;  7,  41, 
143,  205,  375,  1899 ;  13,  75,  1902. 

Echinoderms,  44,  125,  1867;  45,  417,  1868;  49,  93,  101,  1870; 
2,  430,  1871;  11,  416,  1876;  49,  127,  199,  1895;  28,  59,  1909; 
35,  477,  1913;  37,  483,  1914;  38,  107,  1914;  S9,  684,  1915. 

Worms,  50,  223,  1870 ;  3,  126,  1872. 

Mollusks,  49,  217,  1870;  50,  405,  1870;  3,  209,  281,  1872;  5, 
465,  1873;  7,  136,  158,  1874;   9,  123,  177,  1875;   10,  213,  1875; 


414  A  CENTUEY  OF  SCIENCE 

12,  236,  1876;  14,  425,  1877;  19,  284,  1880;  20,  250,  251,  1880; 
2,  74,  91,  1896 ;  3,  51,  79,  162,  355,  1897. 

Crustacea,  44,  126,  1867;  48,  244,  430,  1869;  25,  119,  534, 
1908. 

Ascidians,  1,  54,  93,  211,  288,  443,  1871;  20,  251,  1880. 

Dredging  operations  and  marine  fauna,  49,  129,  1870 ;  2,  357, 
1871;  5,  1,  98,  1873;  6,  435,  1873;  7,  38,  131,  405,  409,  498, 
608,  1874;  9,  411,  1875;  10,  36,  196,  1875;  16,  207,  371,  1878; 
17,  239,  258,  309,  472,  1879 ;  18,  52,  468,  1879 ;  19,  137,  187,  20, 
390,  1880;  22,  292,  1881;  23,  135,  216,  309,  406,  1882;  24,  360, 
477,  1882;  28,  213,  378,  1884;  29,  149,  1885. 

Miscellaneous,  39,  221,  1865;  41,  249,  268,  1866;  44,  126, 
1867;  48,  92,  1869;  3,  386,  1872;  7,  134,  1847;  10,  364,  1875; 
16,  323,  1878;  20,  251,  1880;  3,  132,  135,  1897;  9,  313,  1900; 
12,  88,  1901;  13,  327,  1902;  14,  72,  1902;  15,  332,  1903;  24, 
179,1907;  29,561,1910. 

S.  I.  Smitli  describes  the  metamorphosis  of  the  Crus- 
tacea (3,  401,  1872;  6,  67,  1873),  species  of  Crustacea  (3, 
373, 1872 ;  7,  601, 1874 ;  9,  476, 1875),  and  dredging  opera- 
tions in  Lake  Superior  (2,  373,  448, 1871).  In  this  series 
occurs  also  a  series  of  papers  on  comparative  anatomy 
and  embryology  from  the  Chesapeake  Zoological  Labora- 
tory in  charge  of  W.  K.  Brooks.  In  the  39th  and  40th 
volumes  of  the  third  series  (1890)  occur  several  papers 
on  evolutionary  topics  by  John  T.  Gulick  (39,  21 ;  40,  1, 
437)  which  have  attracted  much  attention. 

Before  the  end  of  this  period,  however,  the  Journal 
was  relieved  from  the  necessity  of  publishing  zoologi- 
cal articles  by  the  establishment  of  several  periodicals 
devoted  especially  to  the  various  fields  of  zoology.  We 
find,  therefore,  but  few  exclusively  zoological  papers 
after  1885,  although  articles  of  a  general  biological  inter- 
est and  the  reviews  of  zoological  books  continue.  ^ 
'  In  the  fourth  series  of  the  Journal,  beginning  in  1896, 
occur  also  a  number  of  articles  on  systematic  zoology  by 
Verrill  and  others  and  several  papers  having  a  general 
biological  interest.  Brief  reviews  of  a  small  number  of 
zoological  books  are  still  continued,  but  at  the  present  day 
the  Journal,  which  played  so  important  a  part  in  the 
early  development  of  American  zoology,  has  been  given 
over  to  the  geological  and  physical  sciences  in  harmony 
with  the  modern  demand  for  specialization. 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     415 

Period  of  Experimental  Biology ,  since  1890, 

Zoological  studies  remained  in  large  measure  observa- 
tional and  comparative  until  about  1890  when  the  experi- 
mental methods  of  Roux,  Driesch  and  others  came  into 
prominence.  Interest  then  turned  from  the  accumulation 
of  facts  to  an  analysis  of  the  underlying  principles  of 
biological  phenomena.  The  question  now  was  not  so 
much  what  the  organism  does  as  how  it  does  what  is 
observed,  and  this  question  could  be  answered  only  by 
the  experimental  control  of  the  conditions.  These  exper- 
imental studies  met  with  such  remarkable  success  that  in 
a  few  years  the  older  morphological  studies  were  largely 
abandoned,  the  Morphological  Society  changed  its  name 
to  the  Society  of  Zoologists,  and  in  1904  the  Journal  of 
Experimental  Zoology  was  established.  The  experimen- 
tal methods  were  applied  to  all  branches  of  biological 
science,  and  while  it  must  be  freely  admitted  that  little 
progress  has  been  made  toward  an  understanding  of  the 
ultimate  causes  which  underlie  biological  phenomena,  a 
great  advance  has  been  made  in  the  elucidation  of  the 
general  principles  involved. 

Experimental  embryology,  histology,  regeneration, 
comparative  physiology,  neurology,  cytology,  and  hered- 
ity have  in  recent  years  successfully  adopted  an  experi- 
mental aspect  and  have  made  significant  progress 
thereby.  Biology  has  now  taken  its  place  beside  chem- 
istry and  physics  as  an  experimental  science. 

The  latest  great  advance  in  biology  has  been  in  the  field 
of  heredity.  The  rediscovery  of  the  Mendelian  principles 
of  heredity  in  1900  brought  to  light  the  most  important 
generalization  in  biology  in  recent  times.  The  new 
science  of  genetics  is  essentially  the  experimental  study 
of  heredity. 

"We  are  at  the  moment  in  the  midst  of  an  effort^  to 
establish  in  biology  a  few  relatively  simple  laws  by  using 
for  the  purpose  the  vast  accumulations  of  observational 
data  gathered  in  past  years,  supplemented  by  such  exper- 
imental data  as  have  been  provided  by  these  more  recent 
investigations.  Such  hypotheses  as  have  been  formu- 
lated are  for  the  most  part  only  tentatively  held,  for  their 


416  A  CENTURY  OF  SCIENCE 

validity  is  generally  incapable  of  a  critical  test.  But 
wherever  such  tests  have  been  possible,  the  laws  of  math- 
ematics, physics  and  chemistry  are  found  applicable  to 
biological  phenomena. 

The  number  of  investigators  has  now  become  so  great 
and  their  activities  so  prolific  that  the  list  and  synopses 
of  the  zoological  publications  each  year  cover  upwards 
of  1000  to  1500  pages  in  the  International  Catalogue  of 
Scientific  Literature. 

American  Leadership. — During  the  first  half  of  the 
century  the  progress  of  zoology  in  America  remained  dis- 
tinctly behind  that  of  Europe.  At  the  beginning  of  the 
century  the  science  was  farthest  developed  by  the  French 
and  English,  although  Linnasus  was  a  Swede  and  took  his 
degree  in  Holland.  Under  the  influence  of  Von  Baer  and 
his  monumental  treatise  on  embryology  (Ueber  Entwick- 
lungsgeschichte  der  Thiere,  1828),  and  supported  later 
by  the  great  physiologist,  Johannes  Miiller,  whose  **Phy- 
siologie  des  Menschen^'  (1846)  forms  the  basis  of  modern 
physiology,  the  German  school  forged  rapidly  ahead  and 
eventually  assumed  the  leadership  in  zoology,  as  in  sev- 
eral other  branches  of  science. 

In  the  latter  half  of  the  century  the  influence  of  the 
German  universities  dominated  in  a  large  measure  the 
zoological  investigations  in  America.  The  reason  for 
this  is  partly  due  to  the  fact  that  many  of  our  young 
zoologists,  after  finishing  their  college  course,  com- 
pleted their  preparation  for  research  by  a  year  or  more 
at  a  German  university.  The  more  mature  zoologists, 
too,  looked  forward  with  keen  anticipation  to  spending 
their  summer  vacations  and  sabbatical  years  in  research 
in  a  German  laboratory  or  at  the  famous  Naples  station 
in  which  the  German  influence  was  dominant. 

With  the  rise  of  experimental  biology  since  1890,  how- 
ever, the  American  zoologists  have  shown  so  high  a  degree 
of  originality  in  devising  experiments,  so  much  skill  in 
performing  them,  and  such  keenness  in  analyzing  the 
results,  that  they  have  assumed  the  world  leadership  in 
several  of  the  special  fields  into  which  the  science  of 
zoology  is  now  divided. 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     417 

Biological  Periodicals, 

Perhaps  in  no  better  way  can  the  progress  of  biology  in 
America  be  illustrated  than  by  a  brief  survey  of  the 
origin  and  development  of  the  more  important  biological 
journals.  For  it  will  be  seen  that  these  publications  have 
become  more  numerous  and  more  specialized  as  the  sci- 
ence has  advanced  in  specialization. 

The  early  publications — ^which  as  is  well  known,  treated 
mainly  of  the  birds,  mammals  and  other  vertebrates,  and 
of  insects,  Crustacea  and  shells — consisted  mainly  of  sep- 
arate books  or  pamphlets,  published  by  private  subscrip- 
tion. After  the  establishment  of  the  so-called  Academies 
of  Science,  or  of  Arts  and  Sciences,  toward  the  end  of 
the  eighteenth  and  in  the  first  quarter  of  the  nineteenth 
century,  the  reports  of  the  meetings  began  to  be  pub- 
lished as  periodical  Journals,  supported  by  the  acade- 
mies. In  these  publications,  and  in  the  Journal  which 
was  founded  at  the  same  time,  appear  papers  on  all 
branches  of  science,  including  zoology.  As  soon  as 
zoology  in  America  assumed  its  modern  aspects  through 
the  influence  of  Louis  Agassiz  and  his  followers  the 
earliest  strictly  zoological  journals  were  established. 

It  should  be  noted,  however,  that  the  journals  of  the 
scientific  and  natural  history  societies  were  more  or  less 
fully  devoted  to  zoological  topics  according  to  the  nature 
of  the  activities  of  the  members  and  correspondents. 
After  the  establishment  of  the  Museum  of  Comparative 
Zoology  by  Louis  Agassiz  came  the  founding  in  1863  of  its 
Bulletin  and  later  its  Memoirs.  These  publications  have 
continued  to  the  present  day  as  a  standard  of  excellence 
for  the  reports  of  zoological  investigations.  In  con- 
nection with  the  systematic  work  on  mollusks,  the  Amer- 
ican Journal  of  Conchology  was  established  in  1865. 
The  American  Naturalist  was  founded  in  1867  by  four  of 
Louis  Agassiz  *s  pupils,  Hyatt,  Morse,  Packard  and  Put- 
nam. It  was  later  edited  by  Cope  as  a  leading  periodical 
for  the  publication  of  biological  papers,  particularly 
those  relating  to  evolution,  and  is  at  present  devoted  to 
evolutionary  topics.  It  is  now  in  the  52d  volume  of  its 
new  series. 


418  A  CENTURY  OF  SCIENCE 

With  the  awakened  interest  in  comparative  anatomy 
and  embryology  came  the  need  for  an  American  journal 
which  should  supply  a  means  of  publication  for  the 
reports  of  researches  accomplished  by  the  increasing 
number  of  workers  in  these  fields.  This  need  was  fully 
met  by  the  establishment  of  the  Journal  of  Morphology 
in  1887.  This  publication,  now  in  its  30th  volume,  has 
equalled  the  best  European  journals  in  the  character  of 
its  papers.  A  few  years  later  (1891)  came  the  Journal 
of  Comparative  Neurology  for  the  publication  of  investi- 
gations relating  to  the  morphology  and  physiology  of  the 
nervous  system  and  to  nervous  and  allied  phenomena  in 
all  groups  of  organisms.  Twenty-eight  volumes  of  this 
journal  have  been  completed.  The  Zoological  Bulletin 
was  started  under  the  auspices  of  the  Marine  Biological 
Laboratory  in  1897  for  the  publication  of  papers  of  a  less 
extensive  nature  and  which  could  be  more  promptly 
issued  than  those  in  the  Journal  of  Morphology  where 
elaborate  plates  were  required.  After  two  years  the 
scope  of  the  Bulletin  was  enlarged  to  include  botanical 
and  physiological  subjects.  The  name  was  correspond- 
ingly changed  to  the  Biological  Bulletin.  Of  this  import- 
ant periodical  33  volumes  have  been  issued. 

For  the  publication  of  papers  on  human  and  compara- 
tive anatomy  and  embryology,  the  American  Journal  of 
Anatomy  was  established  in  1901,  and  is  now  in  its 
twenty-third  volume. 

Meanwhile  the  trend  of  zoological  interest  was  toward 
topics  connected  with  the  ultimate  nature  of  biological 
phenomena.  The  meaning  of  these  phenomena  could  be 
determined  only  by  the  experimental  method.  Researches 
in  this  field  became  more  prominent  and  the  adequate 
publication  of  the  numerous  papers  required  the  estab- 
lishment of  a  new  journal  in  1904.  This  was  named  the 
Journal  of  Experimental  Zoology.  It  immediately  took 
its  place  in  the  front  rank  of  American  zoological  period- 
icals.    Twenty-four  volumes  have  been  published. 

In  spite  of  the  constantly  increasing  number  of 
journals,  the  science  grew  faster  than  the  means  of  pub- 
lication. So  crowded  did  the  American  journals  become 
that  long  delays  often  resulted  before  the  results  of  an 
investigation  could  be  issued.     This  condition  was  met  in 


A  CENTUEY  OF  ZOOLOGY  IN  AMERICA     419 

part  by  the  sending  of  many  papers  to  be  published  in 
European  journals  (a  necessity  most  discreditable  to 
American  zoology)  and  in  part  by  the  establishment 
ef  additional  means  of  publication.  Of  the  latter  the 
Anatomical  Record,  now  in  its  fourteenth  volume,  was 
begun  in  1906  for  the  prompt  publication  of  briefer 
papers  on  vertebrate  anatomy,  embryology  and  histology 
and  for  preliminary  reports  and  notes  on  technique. 

During  the  past  few  years  has  come  a  great  advance  in 
the  experimental  breeding  of  plants  and  animals.  Prob- 
lems in  heredity  and  evolution  have  taken  on  a  new 
interest  since  the  importance  and  validity  of  MendePs 
discovery  have  been  recognized.  To  meet  this  develop- 
ment of  biology  the  journal  Genetics  was  begun  in  1916 
for  the  publication  of  technical  papers,  while  the  Journal 
of  Heredity,  modified  from  the  American  Breeders  Maga- 
zine, is  devoted  to  popular  articles  on  animal  and  plant 
breeding,  and  Eugenics. 

On  the  whole,  the  science  of  zoology  is  now  assuming 
a  closer  relation  to  practical  affairs.  Entomology,  for 
example,  is  now  represented  by  the  Journal  of  Economic 
Entomology,  of  which  10  volumes  have  been  issued  since 

1907.  The  Journal  of  Animal  Behavior  covers  another 
practical  field  of  research.  The  Proceedings  of  the  Soci- 
ety for  Experimental  Biology  and  Medicine,  starting  in 
1903,  the  American  Journal  of  Physiology,  and  several 
other  publications  cover  the  physiological  field.  The 
Journal  of  Parasitology,  established  1914,  now  in  its 
fourth  volume,  is  devoted  to  the  interests  of  medical 
zoology.  The  Auk,  now  in  the  34th  volume  of  its  new 
series  (42d  of  old  series),  is  the  official  organ  of  the  Amer- 
ican Ornithologists  Union  and  is  devoted  to  the  dissemi- 
nation of  knowledge  concerning  bird  life.  The  Annals 
of  the  Entomological  Society  of  America,  established  in 

1908,  and  now  in  its  10th  volume,  is  one  of  several  import- 
ant entomological  journals.  The  Nautilus,  of  which  28 
volumes  have  been  issued,  is  one  of  the  more  successful 
journals  devoted  to  conehology.  This  list  might  be 
extended  to  include  numerous  other  periodicals  of  import- 
ance, both  technical  and  popular,  which  have  been  of  great 
service  in  the  various  fields  of  biology. 

In  addition  to  these  are  the  many  volumes  of  syste- 


420  A  CENTURY  OF  SCIENCE 

matic  papers  in  the  Proceedings  of  the  United  States 
National  Museum,  the  practical  reports  in  the  Bulletin  of 
the  United  States  Fish  Commission,  the  vast  literature 
issued  yearly  by  the  various  divisions  of  the  United 
States  Department  of  Agriculture,  Public  Health  Service 
and  other  Governmental  departments,  while  the  list  of 
publications  by  scientific  societies,  museums,  and  other 
institutes  is  constantly  increasing  and  covers  all  fields  of 
biological  research. 

At  the  present  time  facilities  for  the  publication  of 
research  on  any  branch  of  zoology  are  as  a  rule  entirely 
adequate.  For  this  highly  satisfactory  condition  the 
science  is  indebted  to  the  support  given  five  of  its  most 
important  journals  by  the  Wistar  Institute  of  Anatomy 
and  Biology. 

Biological  Associations. 

An  important  light  on  the  history  of  biology  in  Amer- 
ica can  be  thrown  by  a  glance  at  the  rise  and  development 
of  societies  or  associations  for  the  report  and  discussion  of 
papers  relating  to  that  branch  of  science.  In  the  first  half 
of  the  nineteenth  century  natural  history  societies  were 
formed  in  most  cities  and  centers  of  learning.  These 
were  very  important  factors  in  the  promotion  of  scientific 
research  as  well  as  in  the  diffusion  of  popular  knowledge 
of  living  things.  The  aims  and  activities  of  twenty-nine 
such  scientific  societies,  many  of  which  were  devoted 
especially  to  natural  history,  are  described  in  one  of  the 
early  volumes  of  the  Journal  (10,  369,  1826).  The  Con- 
necticut Academy  of  Arts  and  Sciences,  dating  from  1799, 
the  Philadelphia  Academy  of  Natural  Sciences  from  1812, 
and  the  New  York  Lyceum  of  Natural  History  (in  1876 
name  changed  to  New  York  Academy  of  Sciences)  from 
1817  are  among  the  oldest  of  those  which  still  exist. 

Of  national  institutions  the  American  Philosophical 
Society  was  founded  in  1743,  the  American  Academy  of 
Arts  and  Sciences  in  1780,  and  the  National  Academy  of 
Sciences  in  1863. 

The  American  Association  for  the  Advancement  of 
Science,  with  its  thousands  of  members,  now;  has  separate 
sections  for  each  of  the  special  branches  of  science.     This 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     421 

great  association  was  organized  in  1848,  as  the  successor 
of  the  Association  of  American  Geologists  and  Natural- 
ists. This  was  itself  a  revival  of  the  American  Geolog- 
ical Society  which  first»met  at  Yale  in  1819.  Its  meetings 
have  given  a  great  support  to  the  scientific  work  of  the 
country. 

The  American  Society  of  Naturalists  was  founded  in 
1883.  The  original  plan  of  the  society  was  for  the  dis- 
cussion of  methods  of  investigation,  administration  and 
instruction  in  the  natural  sciences,  but  its  program  is 
now  entirely  devoted  to  discussions  and  papers  of  a  broad 
biological  interest.  It  also  arranges  for  an  annual  din- 
ner of  the  several  biological  societies  and  an  address 
on  some  general  biological  topic. 

In  1890,  toward  the  end  of  the  period  in  which  morpho- 
logical studies  were  being  emphasized,  the  professional 
zoologists  of  the  eastern  states  founded  the  American 
Morphological  Society.  This  association  held  annual 
meetings  during  the  Christmas  holidays  for  the  presenta- 
tion of  zoological  papers.  This  name  became  less  appro- 
priate after  a  few  years  because  of  the  gradual  decrease 
in  the  proportion  of  morphological  investigations  owing 
to  the  greater  attention  being  directed  to  problems  in 
experimental  zoology  and  physiology.  Consequently  the 
name  was  changed  to  the  American  Society  of  Zoologists. 
To  be  eligible  for  membership  in  this  society  a  person 
must  be  an  active  investigator  in  some  branch  of  zoology, 
as  indicated  by  the  published  results. 

The  American  Association  of  Anatomists  includes  in 
its  membership  investigators  and  teachers  in  compara- 
tive anatomy,  embryology,  and  histology  as  well  as  in 
human  anatomy.  Many  professional  zoologists  and 
experimental  biologists  present  their  papers  before  this 
society,  or  at  the  meetings  of  the  American  Physiological 
Society.  The  Entomological  Society  of  America  and  the 
American  Association  of  Economic  Entomologists  are 
large  and  active  societies. 

These  national  societies  have  been  of  great  service  in 
fostering  a  high  standard  of  zoological  research.  A  still 
more  important  service,  though  generally  less  conspicu- 
ous, is  rendered  by  the  journal  clubs  in  connection  with 
all  the  larger  zoological  laboratories,  and  by  local  scien- 


422  A  CENTURY  OF  SCIENCE 

tific  societies  which  are  now  maintained  in  all  the  larger 
centers  of  learning  throughout  the  country.  There  are 
also  specific  societies  for  some  of  the  different  fields  of 
biological  work. 

Biological  Stations, 

No  insignificant  factor  in  the  development  of  biological 
science  has  been  the  establishment  of  biological  stations 
where  investigators,  teachers  and  students  meet  in  the 
Summer  vacation  for  special  studies,  discussions  and 
research.  The  most  successful  of  these  laboratories  have 
been  located  on  the  seashore  and  here  the  study  of  marine 
life  in  Summer  supplements  the  work  of  the  school  or  uni- 
versity biological  courses.  The  famous  Naples  Station 
was  founded  in  1870,  and  was  shortly  after  followed  by 
several  others.  Similar  biological  stations  are  now  sup- 
ported on  almost  every  coast  in  Europe  and  in  several 
inland  localities. 

The  first  such  American  school  was  established  by 
Louis  Agassiz  at  the  island  of  Penikese  on  the  coast  of 
Massachusetts  in  1873,  succeeding  his  private  laboratory 
at  Nahant.  During  that  Summer  more  than  forty  stu- 
dents gained  enthusiasm  for  the  work  of  future  years. 
Unfortunately  the  laboratory  so  auspiciously  started  was 
of  brief  duration,  for  the  death  of  Agassiz  occurred  in 
December  of  the  same  year,  and  the  laboratory  was  dis- 
continued at  the  end  of  the  following  Summer.  Shortly 
afterward  Alexander  Agassiz  equipped  a  small  private 
laboratory  at  Newport,  Rhode  Island,  and  W.  K.  Brooks 
established  the  Chesapeake  Bay  Zoological  Laboratory. 

At  this  time  the  United  States  Fish  Commission  was 
engaged  under  the  direction  of  Spencer  F.  Baird  in  a 
survey  of  the  marine  life  of  the  waters  off  the  Eastern 
Coast.  Between  1881  and  1886  the  Commission  estab- 
lished the  splendidly  equipped  biological  station  at 
Woods  Hole,  Massachusetts.  Both  here  and  at  the  Fish 
Commission  Laboratory  at  Beaufort,  North  Carolina, 
much  work  in  general  zoology  as  well  as  in  economic  prob- 
lems is  accomplished.  These  laboratories  are  designed 
particularly  for  specialists  engaged  in  researches  con- 
nected with  the  work  of  the  Fish  Commission. 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     423 

A  need  was  soon  felt  for  a  marine  laboratory  along 
broader  lines,  and  one  available  to  the  students  and 
teachers  of  the  schools  and  colleges.  To  meet  these 
requirements  the  Woods  Hole  Marine  Biological  Labora- 
tory was  started  in  1887,  as  the  successor  to  an  earlier 
laboratory  at  Annisquam,  and  has  since  become  a  great 
Summer  congress  for  biologists  from  all  parts  of  the 
country.  It  is  safe  to  say  that  no  other  institution  has 
been  of  equal  service  in  securing  for  biology  the  high 
plane  it  now  occupies  in  American  science.  The  leading 
spirit  in  the  establishment  of  this  laboratory  and  its 
director  for  many  years  was  Charles  0.  Whitman. 

Successful  marine  laboratories  are  located  also  at  Cold 
Spring  Harbor,  Long  Island ;  at  Harp  swell,  Maine ;  and 
at  Bermuda.  The  Carnegie  Institution  maintains  a  lab- 
oratory at  Tortugas  Island,  Florida,  for  the  investigation 
of  tropical  marine  life. 

On  the  Pacific  Coast  marine  laboratories  are  located 
at  Pacific  Grove  and  at  La  Jolla,  California,  and  at  Fri 
day  Harbor,  Washington.  Several  other  biological  lab- 
oratories are  open  each  Summer  on  our  coasts,  as  well  as 
a  number  of  fresh-water  laboratories  on  the  interior 
lakes.  There  are  also  several  mountain  laboratories. 
The  influence  of  these  laboratories  on  American  biology 
is  immeasurable. 

Natural  History  Museums, 

Museums  of  Natural  History  or  *^  Cabinets  of  Natural 
Curios''  as  they  were  sometimes  called,  were  established 
in  the  first  half  of  the  nineteenth  century  in  connection 
with  the  various  natural  history  societies.  These  were 
of  much  service  in  stimulating  the  collection  of  zoological 
** specimens"  and  in  arousing  a  popular  interest  in 
natural  history. 

The  zoological  museum  of  earlier  days  consisted  of 
rows  on  rows  of  systematically  arranged  specimens,  each 
carefully  labelled  with  scientific  name,  locality,  date  of 
collection  and  donor — much  like  the  pages  of  a  catalogue. 
All  this  has  now  been  changed ;  the  bottles  of  specimens 
have  been  relegated  to  the  storeroom,  and  the  great 
plate  glass  cases  of  the  modern  museum  represent  indi- 
vidual studies  in  the  various  fields  of  modern  zoological 


424  A  CENTUEY  OF  SCIENCE 

research,  or  individual  chapters  in  the  latest  biological 
text-books.  Often  the  talent  of  the  artist  and  the  skill 
of  the  taxidermist  are  cunningly  combined  to  produce 
most  realistic  bits  of  nature. 

The  United  States  National  Museum,  the  American 
Museum  of  Natural  History,  the  Field  Columbian  Museum 
and  the  Museum  of  Comparative  Zoology  are  among  the 
finest  museums  of  the  world,  while  many  of  the  states, 
cities,  and  universities  maintain  public  museums  as  a 
part  of  their  educational  systems. 

Systematic  Zoology  and  Taxonomy, 

The  work  in  systematic  zoology  is  now  mainly  carried 
on  by  specialists  in  relatively  small  groups  of  animals. 
This  is  necessitated  both  by  the  increasingly  large  num- 
ber of  species  known  to  science  and  by  the  completeness 
and  exactness  with  which  species  must  now  be  defined. 
The  majority  of  systematic  workers  are  now  connected 
with  museums  where  the  large  collections  furnish  mate- 
rial for  comparative  studies. 

Prominent  in  this  field  is  the  United  States  National 
Museum,  the  publications  of  which  are  mainly  taxonomic 
and  zoogeographic,  and  cover  every  group  of  organism. 
The  adequacy  of  this  great  museum  for  such  studies 
may  be  illustrated  by  the  collection  of  mammals.  This 
museum  has  the  types  of  1135  of  the  2138  forms  (includ- 
ing species  and  subspecies)  of  North  American  mammals 
recognized  in  Miller's  list,*  and  less  than  200  forms  lack 
representatives  among  the  120,000  specimens  of  mam- 
mals. Systematic  monographs  of  several  of  the  orders 
of  mammals  have  been  published. 

Systematic  study  of  the  birds  has  brought  the  number 
of  species  and  subspecies  known  to  inhabit  North  and 
Middle  America  to  above  3000.  The  most  comprehen- 
sive systematic  treatise  is  the  still  incomplete  report  of 
Eidgeway^  of  which  seven  large  volumes  have  already 
been  issued. 

On  the  reptiles,  the  most  complete  monograph  is  that 
by  Cope^  entitled  *'The  Crocodilians,  Lizards  and  Snakes 
of  North  America. ' ' 

The  Amphibia  have  also  been  studied  by  Cope,  whose 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     425 

report  on  the  Batrachia  of  North  America'^  is  the  stand- 
ard taxonomic  work. 

The  most  comprehensive  systematic  work  on  fishes  is 
the  ^'Descriptive  Catalogue  of  the  Fishes  of  North  and 
Middle  America''  by  Jordan  and  Evermann.^ 

The  invertebrate  groups  have  been  in  part  similarly 
monographed  by  the  members  of  the  U.  S.  National 
Museum  staff  and  others,  and  further  studies  are  in  prog- 
ress. Other  taxonomic  monographs  published  by  this 
museum  include  the  various  groups  of  animals  from 
many  different  parts  of  the  world. 

A  number  of  the  larger  State,  municipal,  and  university 
museums  publish  bulletins  on  special  groups  represented 
in  their  collections  as  well  as  articles  of  general  zoological 
interest. 

Expeditions,  subsidized  by  museum  and  private  funds, 
are  from  time  to  time  sent  to  various  parts  of  the  world 
and  their  results  are  often  published  in  sumptuous 
manner. 

The  total  number  of  living  species  of  animals  is 
unknown,  but  considering  that  about  a  quarter  of  a  mil- 
lion new  species  have  been  described  during  the  past 
thirty  years,  it  is  probable  that  several  million  species  are 
in  existence  to-day.  More  than  half  a  million  have  been 
described.  These  are  probably  but  a  small  fraction  of 
the  number  that  have  existed  in  past  geological  ages. 

Thus,  in  spite  of  all  the  work  that  has  been  done  in  sys- 
tematic zoology  and  as  the  number  of  known  species  con- 
tinues to  increase,  there  still  remain  many  groups  of 
animals,  some  of  which  are  by  no  means  rare  or  minute, 
in  which  probably  only  a  small  proportion  of  the  species 
are  as  yet  capable-  of  identification. 

It  is  only  since  the  publication  of  Ward  and  Whipple 's 
** Fresh-water  Biology"  within  the  past  year  that  the 
amateur  zoologist  could  hope  to  find  even  the  names  of 
all  the  organisms  which  may  be  collected  from  a  single 
pool  of  water.  And  in  many  cases  he  will  still  meet  with 
disappointment,  for  many  of  our  protozoa  and  other 
fresh-water  organisms  have  not  yet  been  described  as 
species. 

During  the  past  few  years  there  has  been  a  tendency  on 


426  A  CENTURY  OF  SCIENCE 

the  part  of  some  of  our  biologists  engaged  in  experimen- 
tal work  to  disparage  the  studies  of  the  systematists.  It 
must  be  granted,  however,  that  both  lines  of  work  are 
essential  to  the  sound  development  of  zoological  science, 
for  experimental  investigations  in  which  the  accurate 
diagnosis  of  species  is  ignored  always  result  in  confusion. 

Ecology. — The  marvelous  modifications  in  structure 
and  instincts  by  which  the  various  animals  are  adapted 
to  their  surroundings  now  forms  a  special  topic  in  biolog- 
ical research  and  one  of  the  most  fascinating.  The  adap- 
tations in  habitat,  time,  behavior,  appearance  and  even 
in  structure  are  found  capable  of  a  certain  individual 
modification  when  studied  experimentally. 

Zoogeography. — Closely  associated  with  systematic 
zoology,  and  indeed  a  part  of  the  subject  in  its  broader 
sense,  is  the  study  of  the  geographical  distribution  of 
animal  species  and  larger  groups. 

Paleontology. — The  geological  succession  of  organisms 
embraces  a  field  where  zoologist  and  geologist  meet. 
The  wonderful  progress  made  by  American  investiga- 
tors is  well  described  in  the  preceding  chapters  on  His- 
torical Geology  and  Vertebrate  Paleontology. 

Biometry, 

Since  Darwin's  theory  of  evolution  postulated  the 
origin  of  new  species  by  means  of  natural  selection,  it 
was  obviously  necessary  in  order  to  apply  a  critical  test 
to  determine  the  precise  limits  of  a  species.  It  was, 
therefore,  proposed  to  subject  a  given  species  to  a  strict 
examination  by  the  application  of  statistical  methods  to 
determine  the  range  of  variation  of  its  members  and  the 
extent  to  which  the  species  intergrades  with  others. 
Other  problems,  particularly  those  concerning  heredity, 
were  treated  in  similar  manner.  This  branch  of  biolog- 
ical science  was  particularly  developed  by  the  English 
School,  led  by  Sir  Francis  Galton,  followed  by  Karl 
Pearson  and  William  Bate  son. 

In  America  the  methods  of  biometry  have  been  utilized 
extensively  by  Charles  B.  Davenport,  Raymond  Pearl,  H. 
S.  Jennings  and  others  in  the  solution  of  problems  in 
genetics  and  evolution.    Their  work  shows  the  great 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     427 

value  of  critical  statistical  analysis  in  the  interpretation 
of  biological  data.  A  thorough  training  in  mathematics 
is  now  found  to  be  hardly  less  important  for  the  biologist 
than  is  a  knowledge  of  physics  and  chemistry,  for  the 
science  of  biometry  has  become  one  of  the  most  important 
adjuncts  to  the  study  of  genetics. 


Comparative  Anatomy  and  E^nhryology, 

Comparative  Anatomy. — Upon  the  foundations  laid 
down  by  Cuvier  a  century  ago  the  present  elaborate 
structure  of  comparative  anatomy  of  animals,  both  verte- 
brate and  invertebrate,  has  been  developed.  Vast  as  is 
the  present  accumulation  of  facts  and  theories  many 
important  problems  still  await  their  solution.  Jeffries 
Wyman  was  long  a  leader  in  this  field,  where  many 
workers  are  now  engaged. 

Embryology. — The  embryological  studies,  so  bril- 
liantly begun  by  Von  Baer  early  in  the  nineteenth  cen- 
tury, are  still  in  progress.  They  have  now  been  extended 
to  the  groups  more  difficult  of  investigation  and  into  the 
earliest  stages  of  fertilization  and  implantation  in  the 
mammals.  Artificial  cultural  methods  have  yielded 
important  results.  Louis  and  Alexander  Agassiz,  Mark, 
Minot,  Brooks,  Whitman,  Conklin  and  E.  B.  Wilson  have 
taken  prominent  parts  in  this  work. 

In  the  early  nineties  embryological  studies  were 
directed  to  the  arrangement  of  cells  in  the  dividing  egg, 
and  there  was  much  discussion  of  ^^cell  lineage '*  in 
development.  Valuable  as  were  these  studies  they  threw 
comparatively  little  light  on  the  general  problems  of 
evolution. 

Experimental  Embryology. — A  more  fertile  field, 
developed  at  the  same  period  and  a  little  later,  was  found 
in  experimental  embryology.  The  discoveries  made  by 
Driesch  and  others  in  shaking  apart  the  cells  of  the  divid- 
ing egg  or  by  destroying  one  or  more  of  these  cells  gave 
a  new  insight  into  the  potency  of  cells  for  compensatory 
and  regenerative  processes.  These  studies  attracted 
many  able  investigators,  who  made  still  further  advance 
by  subjecting  the  germ  cells,  developing  eggs,  embryos, 


428  A  CENTURY  OF  SCIENCE 

and  developing  organs  to  a  great  variety  of  artificial  con- 
ditions. 

Artificial  Parthenogenesis. — ^Another  question  concerns 
the  nature  of  the  process  of  fertilization  and  the  agencies 
which  cause  the  fertilized  egg  to  develop  into  an  embryo. 
In  1899  Jacques  Loeb  succeeded  in  causing  development 
in  unfertilized  sea-urchin  eggs  by  subjecting  them  to  con- 
centrated sea  water  for  a  period  and  then  returning  them 
to  their  normal  environment.  To  this  promising  field  of 
experimental  work  came  many  of  the  foremost  biologists 
both  in  America  and  Europe.  It  was  soon  found  that 
the  eggs  of  most  groups  of  animals  except  the  higher 
vertebrates  could  be  made  to  develop  into  more  or  less 
perfect  embryos  and  larval  forms  by  treatment  with  a 
great  variety  of  chemical  substances,  by  increased  tem- 
perature, by  mechanical  stimuli  and  by  other  means. 
This  artificial  parthenogenesis,  as  it  is  called,  has  also 
been  successful  in  plants  {Fucus),  and  recently  Loeb  has 
reared  several  frogs  to  sexual  maturity  by  merely 
puncturing  with  a  sharp  needle  the  eggs  from  which  they 
were  derived.  Loeb,  then,  maintains  that ' '  the  egg  is  the 
future  embryo  and  animal;  and  that  the  spermatozoon, 
aside  from  its  activating  effect,  only  transmits  Mendelian 
characters  to  the  egg. '  '^ 

Further  experimental  analyses  of  the  nature  of  the  fer- 
tilization mechanism  have  recently  been  made  by  Mor- 
gan, Conklin,  F.  R.  Lillie,  and  others. 

Germinal  Localization. — The  question  as  to  whether  the 
egg  contains  localized  organ-forming  substances  has  been 
studied  experimentally  particularly  by  means  of  the  cen- 
trifuge. The  results  indicate  that  neither  of  the  older 
opposing  theories  of  ^^performation"  or  *^epigenesis''  is 
applicable  to  all  eggs,  but  that  in  certain  organisms  the 
eggs  possess  a  well-marked  differentiation  while  in 
others  each  part  of  the  egg  is  essentially,  although  prob- 
ably not  absolutely,  equipotential. 

The  Germplasm  Cycle. — Since  "Weismann's  postula- 
tion  of  the  independence  of  soma  and  germplasm  in  1885 
many  attempts  have  been  made  to  trace  the  path  of  the 
hereditary  substance  from  one  generation  to  the  next. 
A  recent  book  by  Hegner^^  summarizes  the  success 
attained  in  various  groups  of  animals. 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     429 

Cytology. 

Another  important  field  of  investigation  which  has 
attracted  many  workers  is  that  which  pertains  to  the  life 
of  the  cell — the  science  of  cytology.  Although  the  cell- 
theory  was  established  as  early  as  1839,  little  advance 
was  made  in  this  subject  in  America  before  1880.  Since 
that  time,  however,  Americans  have  been  so  successful  in 
cytological  discoveries  that  they  are  now  among  the 
world's  leaders  in  this  field. 

These  studies  have  been  followed  along  both  descrip- 
tive and  experimental  lines.  The  most  prominent  of  the 
early  workers  in  this  field  are  E.  L.  Mark  and  E.  B.  Wil- 
son. Mark's  description  of  the  maturation,  fecundation, 
and  segmentation  of  the  ^gg  is  the  most  accurate  and 
complete  of  the  early  cytological  studies.  Wilson's 
discoveries  concerning  the  details  of  fertilization  and 
his  **  Atlas  of  Fertilization  and  Karyokinesis, "  pub- 
lished in  1895,  have  now  become  classic.  Wilson,  too, 
has  published  the  only  American  text-book  on  cytology ,^^ 
and  has  more  recently  taken  the  lead  in  studies  con- 
cerning the  relation  between  the  chromosomes  and  sex. 
Besides  Wilson,  Montgomery,  Mark,  McClung,  Morgan, 
Miss  Stevens,  Conklin  and  their  associates  and  students 
have  now  furnished  conclusive  evidence  that  the  sex  of 
an  organism  is  determined  by,  or  associated  with,  the 
nuclear  constitution  of  the  fertilized  ^gg.  This  consti- 
tution is  moreover  shown  to  be  dependent  upon  the  chro- 
mosomes received  from  the  germ  cells. 

This  explanation  is  in  strict  accordance  with  the  results 
of  experimental  breeding.  It  is  also  quite  in  harmony 
with  the  Mendelian  law  of  inheritance,  and  in  fact  forms 
one  of  the  strongest  supports  for  the  view  that  all  Men- 
delian factors  are  resident  in  the  chromosomes.  Recent 
work  has  also  discovered  the  mechanism  which  governs 
the  complicated  conditions  of  sex  which  occur  in  those 
animals  which  exhibit  alternating  sexual  and  partheno- 
genetic  generations.  These  remarkable  processes  are  in 
all  cases  found  to  depend  upon  a  definite  distribution  of 
the  chromosomes. 

Other  recent  experimental  work  has  shown  that  while 
the  sex  is  thus  normally  determined  in  the  fertilized  eggy 

27 


430  A  CENTURY  OF  SCIENCE 

it  is  in  some  animals  not  irrevocably  fixed,  and  the  normal 
effect  of  the  sex  chromosomes  may  be  inhibited  by 
abnormal  conditions  in  the  developing  embryo,  as  is 
demonstrated  by  the  recent  work  of  Lillie  and  others. 

The  cytological  basis  for  Mendelian  inheritance  has 
been  very  extensively  studied  by  Morgan  and  his  pupils 
in  connection  with  their  work  on  inheritance  in  the  com- 
mon fruit  fly  Drosophila.  The  evidence  supports  Weis- 
mann's  earlier  hypothesis  that  the  chromosomes  are  the 
bearers  of  the  heritable  factors,  and  that  these  are 
arranged  in  a  series  in  the  different  chromosomes.  This 
theory  is  shown  to  be  in  such  strict  accord  with  both  the 
cytological  studies  and  the  results  of  experimental  breed- 
ing that  Morgan  has  ventured  to  indicate  definite  points 
in  particular  chromosomes  as  the  loci  of  definite  heri- 
table factors,  or  genes. 

Confirmation  of  this  view  is  furnished  by  the  behavior 
of  the  so-called  sex-linked  characters,  the  genes  for  which 
are  situated  in  the  same  chromosome  as  that  which 
carries  the  sex  factor.  Many  ingenious  breeding  experi- 
ments indicate  further  that  all  the  hereditary  characters 
in  Drosophila  are  borne  in  four  great  linkage  groups 
corresponding  with  the  four  pairs  of  chromosomes  which 
the  cells  of  this  fly  possess. 

Comparative  Physiology, 

None  of  the  experimental  fields  has  been  of  greater 
importance  in  zoological  progress  than  that  which  con- 
cerns the  functions  of  the  various  organs.  Without  this 
companion  science  morphology  and  comparative  anatomy 
would  have  become  unintelligible.  American  investiga- 
tors, among  whom  G.  H.  Parker  stands  prominent,  have 
taken  a  leading  part  in  this  field  also. 

Neurology. — The  physiological  analysis  of  the  com- 
ponents of  the  nervous  system,  both  in  vertebrates  and 
invertebrates,  is  another  important  branch  of  experimen- 
tal biology.  The  28  volumes  of  the  Journal  of  Compara- 
tive Neurology  attest  the  large  influence  that  American 
investigators  have  had  in  the  development  of  this  science. 

Regeneration. — Experimental  studies  on  the  powers 
of  regeneration  in  plants  and  animals  have  been  made 
from  the  earliest  times.     During  the  past  few  years,  how;- 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     431 

ever,  there  has  been  made  a  concerted  attempt  to  analyze 
the  factors  which  determine  the  amount  and  rate  of 
regeneration.  Much  progress  has  been  made  toward  the 
postulation  of  definite  laws  applicable  to  the  regenerative 
processes  of  the  parts  of  each  organism.  The  critical 
analyses  of  Morgan,  Loeb  and  Child  have  been  particu- 
larly stimulating. 

Tissue  Culture. — Another  line  of  experimental  work 
which  has  been  developed  within  the  past  few  years  by 
Harrison,  Carrell,  and  others  is  the  culture  of  body 
tissues  in  artificial  media.  These  experiments  have 
included  the  cultivation  in  tubes  or  on  glass  slides  of  the 
various  tissues  of  numerous  species  of  animals.  They 
have  yielded  much  information  regarding  the  structure, 
growth  and  multiplication  of  cells,  the  formation  of  tis- 
sues, and  the  healing  of  wounds. 

Transplantation  and  Grafting. — Closely  associated 
experiments  consist  in  the  transplantation  of  organs  or 
other  portions  of  the  body  to  abnormal  positions,  to  the 
bodies  of  other  animals  of  the  same  species  or  of  other 
species.  In  this  way  much  has  been  learned  about  the 
potentiality  of  organs  for  self-differentiation,  for  regula- 
tion, for  regeneration  and  for  compensatory  adaptations. 
The  experiments  have  shown,  further,  the  independence 
of  soma  and  germplasm  and  have  revealed  the  nature  of 
certain  organs  whose  functions  were  previously  obscure. 

Tropisms  and  Instincts. — Another  field  of  experimen- 
tal biology  concerns  the  analysis  of  behavior  of  organ- 
isms in  response  to  various  forms  of  stimuli.  These 
studies  are  being  prosecuted  on  all  groups  of  organisms, 
including  the  larval  stages  of  many  animals,  and  are 
yielding  most  remarkable  results.  The  success  in  this 
field  of  research  is  largely  due  to  stimulating  influence  of 
Jacques  Loeb,  Parker,  Jennings,  and  their  co-workers. 

Biological  Chemistry. — Still  another  experimental  field 
which  has  developed  into  one  of  the  most  important  of 
the  biological  sciences  relates  to  the  fundamental  chem- 
ical and  physical  changes  which  underlie  all  organic  phe- 
nomena. A  knowledge  of  both  physiological  and  physi- 
cal chemistry  is  to-day  essential  for  all  advanced 
biological  work.  The  peculiar  nature  of  life  itself,  of 
growth,  disease,  old-age,  degeneration,  death  and  dissolu- 


432  A  CENTURY  OF  SCIENCE 

tion  are  presumably  only  manifestations  of  chemical  and 
physical  laws.  The  ultimate  goal  of  all  experimental 
biology,  therefore,  will  be  reached  only  when  the  basic 
physico-chemical  properties  of  life  are  understood.  At 
that  time  only  will  the  perennial  controversy  between 
vitalism  and  mechanism  be  ended. 


Economic  Zoology. 

A  moment's  reflection  will  show  that  economic 
biology  is  the  most  essential  of  all  sciences  to  the  human 
welfare  and  progress.  For  man's  relation  to  his  envi- 
ronment is  such  that  the  penalty  for  ignorance  or  neg- 
lect of  the  biological  principles  involved  in  the  struggle 
for  existence  quickly  overwhelms  him  with  a  horde  of 
parasites  or  other  enemies. 

It  is  only  by  the  intelligent  application  of  biological 
knowledge  that  our  food  supplies,  our  forests,  our  domes- 
ticated animals  and  our  bodies  can  be  protected  from  the 
ever  ravenous  organisms  which  surround  us. 

The  losses  to  food  supplies  and  other  products  by 
insects  alone  amounts  to  100  millions  of  dollars  a  month 
in  the  United  States.  And  the  parasites  cause  losses  in 
sickness  and  premature  deaths  each  year  of  many  mil- 
lions more.  Then  there  are  the  destructive  rodents  and 
other  animals  which  add  largely  to  our  burdens  of  sup- 
port. These  enemies  next  to  wars  and  fungi  are  the  most 
destructive  agencies  on  earth.  Could  they  but  be  elim- 
inated man's  struggle  against  opposing  forces  would  be 
in  large  measure  overcome.  The  results  of  recent  work 
in  economic  zoology,  both  in  regard  to  the  destruction  of 
enemies  and  protection  of  useful  mammals,  birds  and 
fishes,  furnish  a  bright  outlook  for  the  future. 

Protozoology. — Partly  as  an  experimental  field  for  the 
solution  of  general  biological  problems  and  partly 
because  of  its  practical  applications  the  study  of  protozoa 
has  now  developed  into  a  special  science. 

The  results  of  the  investigations  of  Calkins,  Woodru:ff, 
Jennings  and  others  have  greatly  supplemented  our 
understanding  of  the  signification  of  such  important 
biological  phenomena  as  reproduction,  sexual  differen- 
tiation, conjugation,  tropisms,  and  metabolism. 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     433 

From  an  economic  standpoint  the  protozoa  have 
recently  been  shown  to  be  of  the  greatest  importance 
because  of  the  human  and  animal  diseases  for  which  they 
are  responsible. 

Parasitology. — The  animal  parasites  of  man,  domesti- 
cated animals  and  plants  include  numerous  species  of 
protozoa,  worms,  and  insects.  Together  with  the  bac- 
teria and  a  few  higher  fungi  they  cause  all  communicable 
diseases.  When  we  consider  that  not  only  our  health 
but  also  our  entire  food  supply  is  dependent  upon  the 
elimination  of  these  organisms  we  must  admit  that  para- 
sitology is  the  most  important  economically  of  all  the 
sciences. 

The  reports  of  the  investigations  of  Stiles  and  his 
associates  in  the  Hygienic  Laboratory  and  of  Ransom 
and  his  staff  in  the  Bureau  of  Animal  Industry  are  widely 
distributed  by  the  federal  government.  The  systematic 
studies  so  ably  begun  by  Joseph  Leidy  in  the  middle  of 
the  last  century  have  been  continued  by  Ward,  Linton, 
Pratt,  Curtis  and  others  on  the  parasites  of  many  groups 
of  animals. 

Economic  Entomology. — Another  extremely  important 
biological  science,  the  practical  applications  of  which  are 
second  only  to  those  of  parasitology  in  importance,  is 
entomology.  In  the  last  few  years  economic  entomology 
has  exceeded  any  of  the  other  branches  of  biology  in  the 
number  of  its  investigators.  The  American  Association 
of  Economic  Entomologists  has  a  membership  of  about 
five  hundred.  The  work  of  most  of  these  is  supported  by 
appropriations  from  the  State  and  federal  governments, 
and  the  results  of  'their  investigations  are  widely 
published. 

It  is  now  well  known  that  some  of  the  protozoon  par- 
asites are  conveyed  from  man  to  man  only  through 
the  bites  of  insects.  The  local  eradication  of  several 
of  our  most  fatal  diseases  has  recently  been  brought 
about  by  the  application  of  measures  to  destroy  such 
insects.  This  is  the  greatest  triumph  of  economic 
zoology. 

Economic  Ichthyology. — The  U.  S.  Fish  Commission 
has  for  many  years  been  actively  engaged  in  investiga- 
tions on  the  food  fishes,  including  methods  for  increasing 


434  A  CENTURY  OF  SCIENCE 

the  food  supply  by  suitable  protection  and  artificial 
propagation.  The  work  includes  also  edible  and  other- 
wise useful  mollusks  and  Crustacea.  Their  marine  and 
fresh-water  laboratories  have  also  been  of  great  service 
to  general  biological  science. 

Economic  Ornithology  and  Mammalogy. — In  addition 
to  the  local  bird  clubs  and  the  American  Ornithologists 
Union  for  the  study  and  preservation  of  bird  and  mam- 
mal life,  the  Bureau  of  Biological  Survey  has  for  some 
years  conducted  investigations  on  the  economic  import- 
ance of  the  various  species.  The  publications  of  this 
Bureau  are  of  gre^t  value  both  in  determining  the 
economic  status  of  our  birds  and  mammals,  and  also  in 
recommending  means  for  the  protection  of  the  beneficial 
species  and  the  destruction  of  the  injurious.  Several  of 
the  States  issue  similar  publications. 

Genetics, 

One  of  the  most  interesting  chapters  in  biology  relates 
to  the  development  of  the  modern  science  of  heredity, 
or  genetics. 

Previous  to  the  year  1900,  when  the  Mendelian  princi- 
ple of  inheritance  was  re-discovered,  the  relative  import- 
ance of  heredity  and  of  environment  in  the  development 
of  an  organism  was  little  understood.  It  is  true  that 
Weismann  had  insisted  on  the  independence  of  soma  and 
germplasm  some  years  earlier  (1883),  but  the  body  of, 
the  individual  was  still  generally  considered  the  key  to 
its  inheritance. 

The  recognition  of  the  general  application  of  Mendel 's 
discovery  gave  a  great  impetus  to  experimental  breeding 
both  in  plants  and  animals.  While  heretofore  it  had  been 
necessary  to  depend  upon  the  somatic  characters  as  evi- 
dence of  the  hereditary  constitution  of  an  individual,  it 
now  became  possible,  knowing  the  hereditary  constitution 
of  the  parents  of  any  pair  of  individuals,  to  predict  with 
almost  mathematical  certainty  the  characters  of  their 
possible  offspring. 

In  general,  the  laws  of  possible  chance  combinations  of 
any  group  of  characters  determine  the  probability  of  any 
particular  offspring  possessing  one  or  many  of  those 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     435 

characters.  The  physical  basis  for  such  Mendelian 
inheritance  is  evidently  the  chance  combinations  of 
chromosomes  which  result  from  the  processes  of  matura- 
tion and  union  of  the  germ  cells. 

Certain  limitations  to  the  law  are  met  with  because 
the  relatively  small  number  of  chromosomes  involves 
linkage  of  genes,  because  of  the  occasional  interchange  of 
groups  of  genes  between  homologous  chromosomes,  and 
because  the  relative  activity  or  potency  of  any  partic- 
ular gene  may  differ  in  different  races,  and,  finally, 
because  the  normal  activity  of  any  given  gene  may  be 
modified  or  inhibited  by  the  action  of  other  genes.  It  is 
by  no  means  certain,  however,  that  all  inheritance  is 
Mendelian,  for  there  still  remains  much  evidence  that  the 
hereditary  basis  of  certain  characters  may  be  resident  in 
the  cytoplasm,  rather  than  in  the  chromosomes.  A 
recent  book  by  Morgan,  Sturtevant,  Miiller  and  Bridges 
(1915),  entitled  *Hhe  mechanism  of  Mendelian  heredity'' 
gives  the  cytological  explanation  of  Mendelian  inher- 
itance. 

Americans  have  from  the  first  taken  a  leading  part  in 
this  field  of  research  and  have  been  quick  to  recognize  its 
practical  applications  to  the  improvement  of  breeds  in 
both  animals  and  plants.  This  prominent  position  is 
largely  due  to  the  experimental  work  of  Castle,  Daven- 
port, Morgan,  Jennings,  Pearl,  and  their  co-workers  on 
animals  and  that  of  East,  Emerson,  Davis,  Hayes  and 
Shull  on  plants. 

The  geneticist  now  realizes  that  the  appearance  of  the 
body  (phenotype)  gives  but  little  clue  to  the  inheritance 
(genotype).  That  two  white  flowers  produce  only  pur- 
ple offspring,  or  two  white  fowls  only  deeply  colored 
chickens,  or  that  a  pair  of  guinea  pigs,  one  of  which  is 
black  and  the  other  white,  have  only  gray  agouti  off- 
spring, while  other  apparently  similar  white  flowers  or 
white  animals  produce  offspring  like  themselves,  is  now 
readily  comprehensible  and  mathematically  predictable. 

The  most  important  application  of  our  newly  acquired 
knowledge  of  inheritance  is  in  the  improvement  of  the 
human  race.  The  wonderful  opportunity  in  this  direc- 
tion must  be  apparent  to  all.  The  welfare  of  humanity 
depends  upon  the  immediate  adoption  of  eugenic  princi- 


436  A  CENTURY  OF  SCIENCE 

pies.     The  Eugenics  Eecord  Office  has  secured  many  of 
the  essential  data. 

With  the  destruction  of  the  world's  best  germ  plasm 
at  a  rate  never  equalled  before,  the  outlook  for  the  future 
race  would  be  appalling  were  it  not  for  the  hope  that  with 
the  advent  of  a  righteous  peace  will  come  a  realization  of 
the  necessity  of  applying  these  new  biological  discoveries 
to  improving  the  races  of  men.  That  the  discoveries 
have  been  made  too  late  in  the  world's  history  to  be  of 
such  use  to  humanity  must  not  be  thought  possible. 

Evolution, 

Previous  to  the  publication  of  Darwin's  '^Origin  of 
Species"  in  1859,  American  zoologists  were  generally 
inclined  toward  special  creation,  in  spite  of  the  evidences 
for  evolution  which  had  been  presented  by  Erasmus  Dar- 
win, Buffon,  Lamarck,  and  Geoffroy  St.  Hilaire.  This 
attitude  of  mind  continued  for  some  years  after  the  pub- 
lication of  the  natural  selection  theory  of  Darwin  and 
Wallace.  This  was  in  part  due  to  the  powerful  influence 
of  Louis  Agassiz  and  others  who  bitterly  opposed  the 
Darwinian  theory.  The  influence  of  Asa  Gray  in  gaining 
a  general  acceptance  for  this  theory  is  explained  in  the 
following  chapter. 

A  modified  Lamarckian  doctrine  was  widely  accepted 
in  the  last  quarter  of  the  century,  due  largely  to  the 
influence  of  Cope,  Hyatt  and  Packard.  The  inheritance 
of  *  *  acquired  characters ' '  demanded  by  this  theory  seems 
incompatible  with  the  discoveries  of  recent  times,  so  that 
*^  today  the  theory  has  few  followers  amongst  trained 
investigators,  but  it  still  has  a  popular  vogue  that  is  wide- 
spread and  vociferous.  "^^ 

The  origin  of  new  varieties  and  species  by  accidental 
and  fortuitous  modifications  (mutations)  of  the  germ- 
plasm  is  now  the  most  widely  accepted  theory  of  evolu- 
tion. 

Some  of  the  most  important  discoveries  regarding  the 
origin  of  new  forms  have  been  recently  made  by  Morgan 
and  his  pupils.  From  a  stock  of  the  common  fruit  fly 
{Drosopfiila  ampelophila)  more  than  125  new  types  have 
arisen  within  six  years.  Each  of  these  types  breeds  true. 
**Each  has  arisen  independently  and  suddenly.     Every 


A  CENTURY  OF  ZOOLOGY  IN  AMERICA     437 

part  of  the  body  has  been  affected  by  one  or  another  of 
these  mutations. ' '  To  arrange  these  mutations  arbi- 
trarily into  graded  series  would  give  the  impression  of  an 
evolutionary  series,  but  this  is  directly  contrary  to  the 
known  facts  concerning  their  origin,  for  each  mutation 
** originated  independently  from  the  wild  type.''  ** Evo- 
lution has  taken  place  by  the  incorporation  into  the  race 
of  those  mutations  that  are  beneficial  to  the  life  and 
reproduction  of  the  individual.''  This  evolutionary 
process  is  usually  accompanied  by  the  elimination  of 
those  forms  which  have  remained  stable  or  which  have 
developed  adverse  mutations. 

A  question  that  is  being  vigorously  debated  at  this 
time  concerns  the  possible  effects  of  selection  on  the 
hereditary  factors.  Are  the  genes  fixed  both  qualita- 
tively and  quantitatively  or  does  a  given  gene  vary  in 
potency  under  different  conditions  and  in  different  indi- 
viduals ?  In  the  former  case  selection  can  only  separate 
the  existing  genes  into  separate  pure  strains.  But  if  the 
gene  be  quantitatively  variable,  then  selection  wiU  result 
in  the  establishment  of  new  types. 

Castle  has  long  stoutly  maintained  the  effect  of  such 
selection,  and  his  forces  have  recently  been  augmented  by 
Jennings.  The  experimental  work  now  in  process  wiU 
doubtless  yield  a  decisive  answer. 

Conclusion, 

A  comparison  of  the  simple  descriptive  natural  history 
of  a  century  ago  with  the  foregoing  manifold  develop- 
ments of  modern  biology  will  indicate  the  wonderful 
progress  which  has  occurred  during  this  period.  The 
path  has  led  from  the  crude  methods  of  the  almost 
unaided  eye  and  hand  to  the  applications  of  the  most 
delicate  experimental  apparatus.  For  the  marvelous 
success  which  zoology  has  attained  has  been  possible  only 
by  the  skillful  use  of  scalpel,  microscope,  microtome  and 
other  mechanical  devices  and  by  the  refined  methods  of 
the  chemist  and  physicist. 

The  central  truth  to  which  all  these  discoveries  consist- 
ently point  is  the  unity  and  harmony  of  all  biological 
phenomena,  and  indeed  of  all  nature.  No  longer  does  the 
zoologist  find  any  demarcated  line  separating  his  field  of 


438  A  CENTURY  OF  SCIENCE 

research  from  that  of  the  botanist  or  the  chemist  or  even 
of  the  physicist,  for  all  the  natural  sciences  obviously  deal 
with  closely  associated  phenomena.  The  aim  of  the 
future  will  be  both  to  complete  fields  of  study  already 
marked  out  and  to  derive  a  comprehensive  explanation 
of  the  general  principles  involved. 

Notes* 

*  Proc.  Biol.  Soc.  Washington,  3,  35,  1886. 

*  Ibid,  4,   9,  1888.      Both  of  these  papers  are  reprinted  in  Ann.  Eept. 
Smithsonian  Inst.,  1897,  U.  S.  Nat.  Mus.,  Pt.  2,  pp.  357-466,  1901. 

'  Louis    Agassiz :     his    Life    and    Correspondence,    by    Elizabeth    Carey 
Agassiz,  p.  145,  1885. 

*  List  of  North  American  Land  Mammals  in  the  United  States  National 
Museum,  1911.     Bull.  79,  U.  S.  Nat.  Mus.,  1912. 

*  Birds  of  North  and  Middle  America,  Bull.  50,  parts  I- VII,  U.  S.  Nat. 
Mus.,  1901-1916. 

« Report  U.  S.  Nat.  Mus.  for  1898,  pp.  153-1270,  1900. 

'  Bull.  34,  U.  S.  Nat.  Mus.,  1889. 

«Bull.  47,  parts  I-IV,  U.  S.  Nat.  Mus.,  1896-1900. 

•J.  Loeb,  The  Organism  as  a  Whole,  p.  126,  1916. 
*°  The  Germ-cell  Cycle  in  Animals,  1914. 

"  The  Cell  in  Development  and  Inheritance,  1896 ;    second  edition,  1900. 
*^  Morgan,  T.  H.     A  critique  of  the  theory  of  evolution,  p.  32,  1916. 


XIII 

THE  DEVELOPMENT  OF  BOTANY  SINCE  1818 

By  GEORGE  L.  GOOD  ALE 

"Our  Botany,  it  is  true,  has  been  extensively  and 
successfully  investigated,  hut  this  field  is  still  rich,  and 
rewards  every  new  research  with  some  interesting  dis- 
covery.^' 

SUCH  are  the  words  with  which  the  sagacious  and 
far-sighted  founder  of  the  American  Journal  of 
Science  and  Arts,  in  his  general  introduction  to  the 
first  volume,  alludes  to  the  study  of  plants.  It  is  plain 
that  the  editor,  embarking  on  this  new  enterprise,  appre- 
ciated the  attractions  of  this  inviting  field  and  sympa- 
thetically recognized  the  good  work  which  was  being  done 
in  it.  It  is  not  surprising,  therefore,  to  find  that  he  wel- 
comed to  the  pages  of  his  initial  number  contributions  to 
botany. 

Early  Botanical  Works, — The  collections  of  dried  and 
living  North  American  plants,  which  had  been  carried 
from  time  to  time  to  botanists  in  Europe,  had  been 
eagerly  studied,  and  the  results  had  been  published  in 
accessible  treatises.  Besides  these  general  treatises, 
there  had  been  issued  certain  works,  wholly  devoted  to 
the  American  Flora.  Among  these  latter  may  be  men- 
tioned Pursh's  ^^ Flora''  (1814)  and  Nuttall's  ^^ Genera'' 
(1818).  There  were  also  a  few  works  which  were  rather 
popular  in  their  character,  such  as  Amos  Eaton's  *' Man- 
ual of  Botany  for  North  America"  (1817),  and  Bigelow's 
** Collection  of  the  Plants  of  Boston  and  environs" 
(1814).  These  handbooks  were  convenient,  and  pos- 
sessed the  charm  of  not  being  exhaustive ;  consequently 
a  botanist,  whether  professional  or  amateur,  was  stimu- 
lated to  feel  that  he  had  a  good  chance  of  enriching  the 
list  of  species  and  adding  to  the  next  edition. 


UO  A  CENTURY  OF  SCIENCE 

The  Early  Tears  of  Botany  in  the  Journal, 

At  that  time,  the  botanists  had  no  journal  in  this 
country  devoted  to  their  science.  Here  and  there  they 
found  opportunity  for  publishing  their  discoveries  in 
some  medical  periodical  or  in  a  local  newspaper.  Hence 
American  botanists  availed  themselves  of  the  welcome 
extended  by  Silliman  to  botanical  contributors  to  place 
their  results  on  record  in  a  magazine  devoted  to  science 
in  its  wide  sense.  Specialization  and  subdivision  of 
science  had  not  then  begun  to  dissociate  allied  subjects, 
and,  consequently,  botanists  felt  that  they  would  be  at 
home  in  this  journal  conducted  by  a  chemist.  Botanists 
responded  promptly  to  this  invitation  with  interesting 
contributions. 

It  is  well  to  remember  that  the  appliances  at  the  com- 
mand of  naturalists  at  the  date  when  the  Journal  began 
its  service,  were  imperfect  and  inadequate.  The  botanist 
did  not  possess  a  convenient  achromatic  microscope,  and 
he  was  not  in  possession  of  the  chemical  aids  now  deemed 
necessary  in  even  the  simplest  research.  Hence,  atten- 
tion was  given  almost  wholly  to  such  matters  as  the 
forms  of  plants  and  the  more  obvious  phenomena  of 
plant-life.  In  view  of  the  poverty  of  instrumental  aids 
in  research,  the  results  attained  must  be  regarded  as  sur- 
prising. 

In  the  very  first  volume  of  the  Journal,  bearing  the  date 
of  1818,  there  are  descriptions  of  four  new  genera  and  of 
four  new  species  of  plants;  certainly  a  large  share  to 
give  to  systematic  botany.  Besides  these  articles,  there 
are  some  instructive  notes  concerning  a  few  plants,  which 
up  to  that  time  had  been  imperfectly  understood.  There 
are  four  Floral  Calendars  which  give  details  in  regard 
to  the  blossoming  and  the  fruiting  of  plants  in  limited 
districts,  a  botanical  subject  of  some  importance  but 
likely  to  become  tedious  in  the  long  run.  Just  here,  the 
skill  of  the  editor  in  limiting  undesirable  contributions  is 
shown  by  his  tactful  remark  designed  to  soothe  the  feel- 
ings of  a  prolix  writer  whose  too  long  list  of  plants  in  a 
floral  calendar  he  had  editorially  cut  down  to  reasonable 
limits.  The  editor  remarks,  **such  extended  observa- 
tions are  desirable,  but  it  may  not  always  be  convenient 


DEVELOPMENT  OF  BOTANY  SINCE  1818     441 

to  insert  very  voluminous  details  of  daily  floral  occur- 
rence." It  is  convenient  to  consider  by  themselves  some 
of  the  botanical  contributions  published  in  the  first  series 
of  volumes  of  the  Journal  during  a  period  of  twenty 
years,  the  period  before  Asa  Gray  became  actively  and 
constantly  associated  with  the  Journal. 

In  systematic  and  geographical  botany  one  finds  com- 
munications from  Douglass  and  Torrey  (4,  56,  1822) 
on  the  plants  of  what  was  then  the  North-west ;  Lewis  C. 
Beck  (10,  257,  1826;  11,  167,  1826;  14,  112,  1828)  contri- 
buted valuable  papers  on  the  botany  of  Illinois  and  Mis- 
souri ;  there  is  a  literal  translation  by  Dr.  Ruschenberger 
(19,  63,  299,  1831;  20,  248,  1831;  23,  78,  250,  1833)  of  a 
very  long  list  of  the  plants  of  Chili ;  Wolle  and  Huebener 
(37,  310,  1839)  gave  an  annotated  catalogue  of  botanical 
specimens  collected  in  Pennsylvania;  Tuckerman  (45,  27, 
1843)  presented  communications  in  regard  to  numerous 
species  which  he  had  examined  critically;  Darlington 
(41, 365, 1841)  published  his  lecture  on  grasses ;  Asa  Gray 
(40,  1,  1841)  gave  an  instructive  account  of  European 
herbaria  visited  by  him,  and  he  contributed  also  a  charm- 
ing account  (42,  1,  1842)  of  a  botanical  journey  to  the 
mountains  of  North  Carolina.  The  most  extensive  series 
of  botanical  communication  at  this  time  was  the  Caricog- 
raphy  by  Professor  Dewey  of  Williams  College,  pre- 
sented in  many  numbers  of  the  Journal ;  the  first  of  these 
in  7,  pp.  264-278,  1824.  There  were  also  descriptions  of 
certain  new  genera,  and  species,  and  critical  studies  in 
synonyms. 

Cryptogamic  botany  is  represented  in  the  first  series 
of  volumes  of  the  Journal  by  L.  C.  Beck's  (15,  287,  1829) 
study  of  ferns  and  mosses,  by  Bailey's  (35,  113,  1839) 
histology  of  the  vascular  system  of  ferns,  by  Fries'  Sys- 
tema  mycologicum  (12,  235,  1829),  and  by  De  Schweinitz 
(9,  397, 1825)  and  Halsey,  who  had  in  hand  a  cryptogamic 
manual.  There  are  two  important  papers  by  Alexander 
Braun,  translated  by  Dr.  George  Engelmann,  one  on  the 
Equisetacese  of  North  America  (46,  81,  1844)  and  the 
other  on  the  Characeae  (46,  92,  1844). 

Vegetable  paleontology  had  begun  to  attract  attention 
in  many  places  in  this  country,  and  therefore  the  trans- 
lated contributions  by  Brongniart  on  fossil  plants  were 


M2  A  CENTURY  OF  SCIENCE 

given  space  in  the  Journal.  Plant-physiology  received 
a  good  share  of  attention  either  in  short  notices  or  in 
longer  articles.  Such  titles  appear  as,  the  respiration  of 
plants,  the  circulation  of  sap,  the  excrementitious  matter 
thrown  off  by  plants,  the  effects  of  certain  gases  and 
poisons  on  plants,  and  the  relations  of  plants  to  different 
colored  light.  One  of  the  most  important  of  the  notes 
is  that  in  which  is  described  the  discovery  by  Robert 
Brown  (19,  393,  1831)  of  the  constant  movement  of 
minute  particles  suspended  in  a  liquid,  first  detected  by 
him  in  the  f  ovilla  of  pollen  grains,  and  now  known  as  the 
Brownian  (or  Brunonian)  movement.  The  heading 
tinder  which  this  note  appears  is  of  interest,  *  *  The  motion 
of  living  particles  in  all  kinds  of  matter. ' ' 

One  side  of  botany  touches  agriculture  and  economics. 
That  side  was  represented  even  in  the  first  volume  of  the 
Journal  by  a  study  of  *Hhe  comparative  quantity  of  nutri- 
tious matter  which  may  be  obtained  from  an  acre  of  land 
when  cultivated  with  potatoes  or  wheat.''  Succeeding 
volumes  in  this  series  likewise  present  phases  which  are 
of  special  interest  regarded  from  the  point  of  view  of 
economics ;  for  example,  those  which  treat  of  rotation  of 
crops  and  of  enriching  the  soil.  Probably  the  economic 
paper  which  may  be  regarded  as  the  most  important,  in 
fact  epoch-making,  is  the  full  account  of  the  invention  by 
Appert  of  a  method  for  preserving  food  indefinitely 
(13,  163,  1828).  We  all  know  that  Appert 's  process  has 
revolutionized  the  preservation  of  foods,  and  in  its  mod- 
ern modification  underlies  the  vast  industry  of  canned 
fruits,  vegetables  and  so  on.  There  are  suggestions, 
also,  as  to  the  utilization  of  new  foods,  or  of  old  foods  in 
a  new  way,  which  resemble  the  suggestions  made  in  these 
days  of  food  conservation.  For  example,  it  is  shown 
that  flour  can  be  made  from  leguminous  seeds  by  steam- 
ing and  subsequent  drying,  and  pulverizing.  There  are 
excellent  hints  as  to  the  best  ways  of  preparing  and  using 
potatoes,  and  also  for  preserving  them  underground, 
where  they  will  remain  good  for  a  year  or  two.  It  is 
shown  that  potato  flour  can  be  made  into  excellent  bread. 
Another  method  of  making  bread,  namely  from  wood,  is 
described,  but  it  does  not  seem  quite   so  practicable. 


DEVELOPMENT  OF  BOTANY  SINCE  1818     443 

There  are  interesting  notes  on  the  sugar-beet  as  a  source 
of  sugar,  and  here  appears  one  of  the  earliest  accounts  of 
the  Assam  tea-plant,  which  was  destined  to  revolutionize 
the  tea  industry  throughout  the  world.  Cordage  and  tex- 
tile fibers  of  bark  and  of  wood  should  be  utilized  in  the 
manufacture  of  paper.  In  fact  one  comes  upon  many 
such  surprises  in  economic  botany  as  the  earlier  volumes 
of  the  Journal  are  carefully  examined. 

Early  numbers  of  the  Journal  present  with  suffi- 
cient fulness  accounts  of  the  remarkable  discovery  by 
Daguerre  and  others  of  a  process  for  taking  pictures  by 
light,  on  a  silver  plate  or  upon  paper  (37,  374,  1839 ;  38, 
97,  1840,  etc.).  Before  many  years  passed,  the  Journal 
had  occasion  to  show  that  these  novel  photographic 
delineations  could  be  made  useful  in  the  investigation  of 
problems  in  botany.  In  the  pages  of  the  Journal  it  would 
be  easily  possible  to  trace  the  development  of  this  art  in 
its  relations  to  natural  history.  Silliman  possessed 
great  sagacity  in  selecting  for  his  enterprise  all  the  nov- 
elties which  promised  to  be  of  service  in  the  advancement 
of  science.  In  1825  (9,  263)  the  Journal  republished 
from  the  Edinburgh  Journal  of  Science  an  essay  by  Dr. 
(afterwards  Sir)  William  Jackson  Hooker,  on  American 
Botany.  In  this  essay  the  author  states  that  *^the 
various  scientific  Journals"  which  ^^are  published  in 
America,  contain  many  memoirs  upon  the  indigenous 
plants.  Among  the  first  of  these  in  point  of  value,  and 
we  think  also  the  first  with  regard  to  time,  we  must  name 
Silliman 's  Journal  of  Science. '^  The  author  enumerates 
some  of  the  contributors  to  the  Journal  and  the  titles  of 
their  papers. 

It  has  been  a  useful  practice  of  the  Journal,  almost 
from  the  first,  to  transfer  to  its  pages  memoirs  which 
would  otherwise  be  likely  to  escape  the  notice  of  the 
majority  of  American  botanists.  The  book  notices  and 
the  longer  book  reviews  covered  so  wide  a  field  that  they 
placed  the  readers  of  the  Journal  in  touch  with  nearly  all 
of  the  current  botanical  literature  both  here  and  abroad. 
These  critical  notices  did  much  towards  the  symmetrical 
development  of  botany  in  the  United  States.  ^  And  as  we 
shall  now  see,  the  Journal  notices  and  reviews  in  the 


444  A  CENTURY  OF  SCIENCE 

hands  of  Asa  Gray  continued  to  be  one  of  the  most 
important  factors  in  the  advancement  of  American 
botany. 

Asa  Gray  and  the  Journal, 

In  1834  there  appears  in  the  Journal  (25,  346)  a 
*' Sketch  of  the  Mineralogy  of  a  portion  of  Jefferson  and 
St.  Lawrence  Counties,  New  York,  by  J.  B.  Crawe  of 
Watertown  and  A.  Gray  of  Utica,  New  York.''  This 
appears  to  be  the  first  mention  in  the  Journal  of  the 
name  of  Dr.  Asa  Gray,  who,  shortly  after  that  date, 
became  thoroughly  identified  with  its  botanical  interests. 
In  the  early  part  of  his  career  both  before  and  imme- 
diately after  graduating  in  medicine.  Gray  gave  much 
attention  to  the  different  branches  of  natural  history  in 
its  wide  sense.  He  not  only  studied  but  taught  *  *  chemis- 
try, geology,  mineralogy,  and  botany, ' '  the  latter  branch 
being  the  one  to  which  he  devoted  most  of  his  attention. 
Among  his  early  guides  in  the  pursuit  of  botany  may  be 
mentioned  Dr.  Hadley,  **who  had  learned  some  botany 
from  Dr.  Ives  of  New  Haven,''  and  Dr.  Lewis  C.  Beck  of 
Albany,  author  of  Botany  of  the  United  States  North  of 
Virginia.  At  that  period  he  made  the  acquaintance 
of  Dr.  John  Torrey  of  New  York,  with  whom  he  later 
became  associated  in  most  important  descriptive  work. 
During  the  years  between  his  graduation  in  medicine  and 
1842,  the  year  when  he  came  to  Harvard  College,  his 
activities  were  diverse  and  intense;  so  that  his  prep- 
aration for  his  distinguished  career  was  very  broad  and 
thorough.  His  first  visit  to  Europe,  in  1838,  brought  him 
into  personal  relations  with  a  large  number  of  the  botan- 
ists of  Great  Britain  and  the  Continent.  This  extensive 
acquaintance,  added  to  his  broad  training,  enabled  him 
even  from  the  outset  to  exert  a  profound  influence  upon 
the  progress  of  his  favorite  science.  He  made  the 
Journal  tributary  to  this  development.  His  name  first 
appears  as  associate  editor  in  1853,  but  there  are  articles 
in  the  Journal  from  his  pen  which  bear  an  earlier  date. 
The  first  of  these  early  botanical  papers  is  the  following: 
**A  Translation  of  a  memoir  entitled  ^Beitrage  zur  Lehre 
von  der  Befruchtung  der  Pflanzen,'  (contributions  to  the 
doctrine   of  the  impregnation  of  plants,  by  A.   J.   C. 


s 


t-s^ 


DEVELOPMENT  OF  BOTANY  SINCE  1818     445 

Corda:)  with  prefatory  remarks  on  the  progress  of  dis- 
covery relative  to  vegetable  fecundation;  by  Asa  Gray, 
M.  D/'  (31,  308,  1837).  Dr.  Gray  says  that  he  made  the 
translation  from  the  German  for  his  own  private  use, 
but  thinking  that  it  might  be  interesting  to  the  Lyceum, 
he  brought  it  before  the  Society,  with  *^a  cursory  account 
of  the  progress  of  discovery  respecting  the  fecundation 
of  flowering  plants,  for  the  purpose  of  rendering  the 
memoir  more  generally  intelligible  to  those  who  are  not 
particularly  conversant  with  the  present  state  of  botan- 
ical science.'*  The  translation  occupies  six  pages  of  the 
Journal,  while  the  prefatory  remarks  fill  nine  pages. 
The  prefatory  remarks  constitute  an  exhaustive  essay  on 
the  subject,  embodied  in  attractive  and  perfectly  clear 
language.  The  translator  shows  complete  familiarity 
with  the  matter  in  hand  and  gives  an  adequate  account  of 
all  the  work  done  on  the  subject  up  to  the  date  of 
M.  Corda 's  paper.  A  second  important  paper  by  him 
near  this  period  is  his  review  of  **A  Natural  System  of 
Botany :  or  a  systematic  view  of  the  Organization,  Natu- 
ral Affinities,  and  Geographical  Distribution  of  the  whole 
Vegetable  Kingdom;  together  with  the  use  of  the  more 
important  species  in  Medicine,  the  Arts,  and  rural  and 
domestic  economy,  by  John  Lindley.  Second  edition, 
with  numerous  additions  and  corrections,  and  a  complete 
list  of  genera  and  their  synonyms.  London:  1836"  (32, 
292,  1837).  A  very  brief  notice  of  this  work  in  the  first 
part  of  the  volume  for  1837  closes  with  the  words,  '*A 
more  extended  notice  of  the  work  may  be  expected  in  the 
ensuing  number  of  the  Journal."  The  extended  notice 
proved  to  be  a  critical  study  of  the  work,  signed  by  the 
initials  A.  G.  which  later  became  so  familiar  to  readers 
of  the  Journal.  Citation  of  a  few  of  its  sentences  will 
indicate  the  strong  and  quiet  manner  in  which  Dr.  Gray, 
even  at  the  outset,  wrote  his  notices  of  books.  In  speak- 
ing of  the  second  edition  of  Professor  Lindley 's  work, 
he  says: 

"It  is  not  necessary  to  state  that  a  treatise  of  this  kind  was 
greatly  needed,  or  to  allude  to  the  peculiar  qualifications  of  the 
learned  and  industrious  author  for  the  accomplishment  of  the 
task,  or  the  high  estimation  in  which  the  work  is  held  in  Europe. 
But  we  may  properly  offer  our  testimony  respecting  the  great 

28 


446  A  CENTURY  OF  SCIENCE 

and  favorable  influence  which  it  has  exerted  upon  the  progress 
of  botanical  science  in  the  United  States.  Great  as  the  merits 
of  the  work  undoubtedly  are,  we  must  nevertheless  be  excused 
from  adopting  the  terms  of  extravagant  and  sometimes  equivocal 
eulogy  employed  by  a  popular  author,  who  gravely  informs  his 
readers  that  no  book,  since  printed  Bibles  were  first  sold  in  Paris 
by  Dr.  Faustus,  ever  excited  so  much  surprise  and  wonder  as 
did  Dr.  Torrey's  edition  of  Lindley's  Introduction  to  the  Natural 
System  of  Botany.  Now  we  can  hardly  believe  that  either  the 
author  or  the  American  editor  of  the  work  referred  to  was  ever 
in  danger,  as  was  honest  Dr.  Faustus,  of  being  burned  for  witch- 
craft, neither  do  we  find  anything  in  its  pages  calculated  to 
produce  such  astonishing  effects,  except,  perhaps,  upon  the 
minds  of  those  botanists,  if  such  they  may  be  called,  who  had 
never  dreamed  of  any  important  changes  in  the  science  since  the 
appearance  of  good  Dr.  Turton's  translation  of  the  Species 
Plantarum,  and  who  speak  of  Jussieu  as  a  writer  who  has  greatly 
improved  the  natural  orders  of  Linnaeus.'' 

In  the  Journal  for  1840  there  is  a  large  group  of 
unsigned  book  reviews  under  the  heading,  **  Brief  notices 
of  recent  Botanical  works,  especially  those  most  inter- 
esting to  the  student  of  North  American  Botany. '  ^  The 
first  of  these  short  reviews  deals  with  the  second  section 
of  Part  VII  of  De  Candolle's  '^Prodromus.''  In  1847 
the  consideration  of  the  ^^Prodromus''  is  resumed  by 
the  same  author  and  the  initials  of  A.  G.  are  appended. 
This  indicates  that  Dr.  Gray  was  probably  the  writer  of 
some  of  the  unsigned  book-reviews  which  had  appeared 
in  the  Journal  between  1837  and  1840.  Doubtless  Silli- 
man  availed  himself  of  the  assistance  of  his  associates, 
Eli  Ives  and  others,  in  New  Haven,  in  the  examination 
of  current  botanical  literature,  and  it  is  extremely  prob- 
able that  he  early  secured  help  from  young  Dr.  Gray, 
who  had  shown  himself  to  be  a  keen  critic  as  well  as  a 
pleasing  writer.  The  notices  of  botanical  works  from 
1840  bear  marks  of  having  been  from  the  same  hand. 
They  cover  an  extremely  wide  range  of  subjects.  While 
they  are  good-tempered  they  are  critical,  and  they  had 
much  to  do  with  the  development  of  botany,  in  this 
country,  along  safe  lines. 

Gray  as  Editor. — Gray's  name  as  associate  editor  of 
the  Journal  appears  in  1853.  He  had  been  a  welcome 
contributor,   as  we  have   seen,   for  many  years.    His 


DEVELOPMENT  OF  BOTANY  SINCE  1818     447 

influence  upon  the  progress  of  botany  in  the  "United 
States  was  largely  due  to  his  connection  with  the  Journal. 
His  reviews  extended  over  a  very  wide  range,  and  supple- 
mented to  a  remarkable  degree  his  other  educational 
work.  It  must  be  permitted  to  allude  here  to  his  sagacity 
as  a  writer  of  educational  treatises.  In  his  first  ele- 
mentary text-book,  published  in  1836,  he  expressed  wholly 
original  views  in  regard  to  certain  phases  of  structure 
and  function  in  plants,  which  became  generally  adopted 
at  a  later  date.  His  Manual  of  Botany  was  constructed, 
and  subsequent  editions  were  kept,  on  a  plan  which  made 
no  appeal  to  those  who  wanted  to  work  on  lines  of  least 
resistance;  in  fact  he  had  no  patience  with  those  who 
desired  merely  to  ascertain  the  name  of  a  plant.  In  the 
Journal  he  emphasizes  the  desirability  of  learning  all  the 
afiinities  of  the  plant  under  consideration.  At  a  later 
period,  when  entirely  new  chapters  had  been  opened  in 
the  life  of  plants,  he  sought  by  his  contributions  in  the 
Journal  to  interest  students  in  this  wider  outlook. 

Professor  C.  S.  Sargent  has  selected  with  good  judg- 
ment some  of  the  more  important  scientific  papers  by 
Professor  Gray  and  has  re-published  them  in  a  con- 
venient form.^  Many  of  these  papers  were  contributed 
to  the  Journal  in  the  form  of  reviews.  These  reviews 
touch  nearly  every  branch  of  the  science  of  botany.  As 
Sargent  justly  says,  **Many  of  the  reviews  are  filled  with 
original  and  suggestive  observations,  and  taken  together, 
furnish  the  best  account  of  the  development  of 
botanical  literature  during  the  last  fifty  years  that  has 
yet  been  written."  In  these  longer  reviews  in  the 
Journal,  Gray  was  wont  to  take  a  book  under  review  as 
affording  an  opportunity  to  illustrate  some  important 
subject,  and  many  of  the  reviews  are  crowded  with 
his  expositions.  For  example,  in  his  examination  of 
vonMohPs  *^ Vegetable  Cell"  (15,  451,  1853)  he  takes  up 
the  whole  subject  of  microscopic  structure,  so  far  as 
it  was  then  understood,  and  he  points  out  the  probable 
errors  of  some  of  MohPs  contemporaries,  showing  what 
and  how  great  were  MohPs  own  contributions  to  his- 
tology. Such  a  review  is  a  landmark  in  the  science.  The 
physiology  of  the  cell  and  the  nutrition  of  th©  plant  were 
favorite  topics  with  Professor  Gray,  and  he  brought 


448  A  CENTURY  OF  SCIENCE 

much  of  his  knowledge  in  regard  to  them  into  such  a 
review  as  that  of  Boussingault  (25,  120,  1858)  on  the 
'**  Influence  of  nitrates  on  the  production  of  vegetable 
matter." 

As  a  systematic  botanist,  Gray  was  naturally  much 
interested  in  the  vexed  question  of  nomenclature  of 
plants.  One  of  his  most  important  communications  to 
the  Journal  is  his  review,  in  the  volume  for  1883  (26, 
417),  of  DeCandolle's  work  on  the  subject.  He  deals 
with  this  strictly  technical  matter  much  as  he  did  in  a 
contribution  to  the  Journal  which  he  made  in  1868  (46, 
63).  In  both  of  these  papers  he  states  with  clearness  the 
general  features  of  the  code  of  nomenclature.  He  says 
explicitly  that  the  code  does  not  make,  but  rather 
declares,  the  common  law  of  botanists.  The  treatment 
of  the  subject  at  his  hands  would  rightly  impress  a  gen- 
eral reader  as  showing  a  strong  desire  to  have  common 
sense  applied  to  doubtful  cases,  instead  of  insisting  on 
inflexible  rules.  For  this  reason,  his  rule  of  practice  was 
not  always  acceptable  to  those  who  were  anxious  to 
secure  conformity  to  arbitrary  rules  at  whatever  cost. 
As  he  said  in  a  paper  published  in  the  Journal  in  1847 
(3,  302),  **The  difficulty  of  a  reform  increases  with  its 
necessity.  It  is  much  easier  to  state  the  evils  than  to 
relieve  them;  and  the  well-meant  endeavors  that  have 
recently  been  made  to  this  end,  are,  some  of  them,  likely, 
if  adopted,  to  make  confusion  worse  confounded."  This 
feeling  led  him  to  be  very  conservative  in  the  matter  of 
reform  in  nomenclature. 

This  subject  of  botanical  nomenclature  illustrates  a 
method  frequently  employed  by  Professor  Gray  to  elu- 
cidate a  difficult  matter.  He  would  find  in  the  treatise 
under  review  a  text,  or  texts,  on  which  he  would  build  a 
treatise  of  his  own,  and  in  this  way  he  made  clear  his  own 
views  relative  to  most  of  the  important  phases  of  botany. 
When  he  faced  controverted  matters,  his  attitude  still 
remained  judicial.  While  he  was  tolerant  of  opinions 
which  clashed  with  his  own,  he  was  always  severe  upon 
charlatanism  and  impatient  of  inaccuracy.  The  pages 
of  the  Journal  contain  many  severe  criticisms  at  his 
hands,  but  an  unprejudiced  person  would  say  that  the 
severity  is  merited. 


DEVELOPMENT  OF  BOTANY  SINCE  1818     449 

Sometimes,  however,  instead  of  reviewing  a  book  or  an 
address,  he  would  follow  the  custom  inaugurated  early  in 
the  history  of  the  Journal,  of  making  copious  extracts, 
and  thus  give  to  its  readers  an  opportunity  of  examining 
materials  which  otherwise  might  not  fall  in  their  way. 

Gray's  contributions  to  the  Journal  comprise  more 
than  one  thousand  titles,  without  counting  the  memorial 
notices  and  the  shorter  obituary  notes.  In  these  notices 
he  sums  up  in  a  few  well-chosen  words  the  contributions 
made  to  botany  by  his  contemporaries.  Even  in  the  few 
instances  in  which  he  felt  obliged  to  note  with  disap- 
proval some  of  the  work,  he  expressed  himself  with  per- 
sonal friendliness.  The  necrology,  as  it  appeared  from 
month  to  month,  was  a  labor  of  love.  All  of  the  longer 
memorial  notices  are  what  it  is  the  fashion  now-a-days 
to  call  appreciations,  and  these  are  so  happily  phrased 
that  it  would  seem  as  if  the  writer  in  many  a  case  asked 
himself,  *  *  Would  my  friend,  about  whom  I  am  now  writ- 
ing, make  any  change  in  this  sketch  T ' 

Gray  on  Darwinism. — In  October,  1859,  Darwin's 
epoch-making  work,  **The  Origin  of  Species,"  was  pub- 
lished. An  early  copy  was  sent  to  the  editor  of  the  Jour- 
nal, Professor  James  D.  Dana.  This  arrived  in  New 
Haven* on  December  21,  but  it  was  preceded  by  a  personal 
letter  which  is  of  so  much  interest  that  it  is  here  tran- 
scribed in  full.  It  should  be  added  that  Dana  was  at  this 
time  in  Europe  where  he  was  spending  a  year  in  the 
search  for  health  after  a  serious  nervous  breakdown. 
In  his  absence  the  book  was  noticed  by  Gray  as  stated 
below.     The  letter  is,  as  follows : 

Down,  Bromley,  Kent. 

Nov.  11th,  1859. 

My  dear  Sir, 

I  have  sent  you  a  copy  of  my  Book  (as  yet  only  an  abstract)  on 
the  Origin  of  Species.  I  know  too  well  that  the  conclusion,  at 
which  I  have  arrived,  will  horrify  you,  but  you  will,  I  believe 
and  hope,  give  me  credit  for  at  least  an  honest  search  after  the 
truth.  I  hope  that  you  will  read  my  Book,  straight  through; 
otherwise  from  the  great  condensation  it  will  be  unintelligible. 
Do  not,  I  pray,  think  me  so  presumptuous  as  to  hope  to  convert 
you ;  but  if  you  can  spare  time  to  read  it  with  care,  and  will  then 
do  what  is  far  more  important,  keep  the  subject  under  my  point 


450  A  CENTURY  OF  SCIENCE 

of  view  for  some  little  time  occasionally  before  your  mind,  I  have 
hopes  that  you  will  agree  that  more  can  be  said  in  favour  of  the 
mutability  of  species,  than  is  at  first  apparent.  It  took  me  many 
long  years  before  I  wholly  gave  up  the  common  view  of  the  sep- 
arate creation  of  each  species.  Believe  me,  with  sincere  respect 
and  with  cordial  thanks  for  the  many  acts  of  scientific  kindness 
which  I  have  received  from  you, 

My  dear  Sir, 
Yours  very  sincerely, 

Charles  Darwin. 

In  March,  1860  (29,  1.53),  Gray  published  in  the  Journal 
an  elaborate  and  cautious  review  of  Darwin's  work.  He 
alluded  to  the  absence  of  the  chief  editor  of  the  Journal 
in  the  following  words : 

*'The  duty  of  reviewing  this  volume  in  the  American  Journal 
of  Science  would  naturally  devolve  upon  the  principal  editor 
whose  wide  observation  and  profound  knowledge  of  various 
departments  of  natural  history,  as  well  as  of  geology,  particu- 
larly qualify  him  for  the  task.  But  he  ha?  been  obliged  to  lay 
aside  his  pen  to  seek  in  distant  lands  the  entire  repose  from 
scientific  labor  so  essential  to  the  restoration  of  his  health,  a 
consummation  devoutly  to  be  wished  and  confidently  to  be 
expected.  Interested  as  Mr.  Dana  would  be  in  this  volume,  he 
could  not  be  expected  to  accept  its  doctrine.  Views  so  idealistic 
as  those  upon  which  his  'Thoughts  upon  Species'  are  grounded, 
will  not  harmonize  readily  with  a  doctrine  so  thoroughly  natur- 
alistic as  that  of  Mr.  Darwin  .  .  .  Between  the  doctrines  of 
this  volume  and  those  of  the  great  naturalist  whose  name  adorns 
the  title-page  of  this  Journal  [Mr.  Agassiz]  the  widest  diver- 
gence appears. ' ' 

Gray  then  proceeds  to  contrast  the  two  views  of  Dar- 
win and  Agassiz,  *^for  this  contrast  brings  out  most 
prominently  and  sets  in  strongest  light  and  shade  the 
main  features  of  the  theory  of  the  origination  of  species 
by  means  of  Natural  Selection. '*  He  then  states  both 
sides  with  great  fairness,  and  proceeds : 

**Who  shall  decide  between  such  extreme  views  so  ably  main- 
tained on  either  hand,  and  say  how  much  truth  there  may  be 
in  each.  The  present  reviewer  has  not  the  presumption  to  under- 
take such  a  task.  Having  no  prepossession  in  favor  of  natur- 
alistic theories,  but  struck  with  the  eminent  ability  of  Mr. 
Darwin's  work,  and  charmed  with  its  fairness,  our  humbler  duty 
will  be  performed  if,  laying  aside  prejudice  as  much  as  we  can, 


DEVELOPMENT  OF  BOTANY  SINCE  1818     451 

we  shall  succeed  in  giving  a  fair  account  of  its  method  and  argu- 
ment, offering  by  the  way  a  few  suggestions  such  as  might  occur 
to  any  naturalist  of  an  inquiring  mind.  An  editorial  character 
for  this  article  must  in  justice  be  disclaimed.  The  plural  pro- 
noun is  employed  not  to  give  editorial  weight,  but  to  avoid  even 
the  appearance  of  egotism  and  also  the  circumlocution  which 
attends  a  rigorous  adherence  to  the  impersonal  style. ' ' 

In  this  review  he  moves  slowly  and  thoughtfully,  but 
not  timidly,  over  the  new  paths.  There  is  no  clear  indi- 
cation in  the  review  that  he  has  yet  made  up  his  mind  as 
to  the  validity  of  Darwin's  hypothesis.  But,  in  a  sec- 
ond article  appearing  in  the  Journal  for  September  of 
the  same  year  (30,  226),  under  the  title  *^  Discussion 
between  two  readers  of  Darwin's  treatise  on  the  origin 
of  species  upon  its  natural  theology''  Gray  plainly  begins 
to  incline  to  take  a  very  favorable  view  of  the.  Darwinian 
theory,  and  makes  use  of  the  following  ingenious  illus- 
tration to  show  that  it  is  not  inconsistent  with  theistic 
design.  A  few  paragraphs  here  quoted  show  the  felicity 
of  his  style  in  a  controverted  matter : 

"Recall  a  woman  of  a  past  generation  and  show  her  a  web 
of  cloth;  ask  her  how  it  was  made,  and  she  will  say  that  the 
wool  or  cotton  was  carded,  spun,  and  woven  by  hand.  When 
you  tell  her  it  was  not  made  by  manual  labor,  that  probably  no 
hands  have  touched  the  materials  throughout  the  process,  it  is 
possible  that  she  might  at  first  regard  your  statement  as  tanta- 
mount to  the  assertion  that  the  cloth  was  made  without  design. 
If  she  did,  she  would  not  credit  your  statement.  If  you 
patiently  explained  to  her  the  theory  of  carding-machines,  spin- 
ning-jennies, and  power-looms,  would  her  reception  of  your 
explanation  weaken  her  conviction  that  the  cloth  was  the  result 
of  design?  It  is  certain  that  she  would  believe  in  design  as 
firmly  as  before,  and  that  this  belief  would  be  attended  by  a 
higher  conception  and  reverent  admiration  of  a  wisdom,  skill, 
and  power  greatly  beyond  anything  she  had  previously  conceived 
possible. ' ' 

By  this  review  Gray  disarmed  hostility  to  such  an 
extent  that  some  persons  who  had  been  antagonistic  to 
Darwinism  accepted  it  with  only  slight  reservation. 
It  may  be  fairly  claimed  that  the  Journal  bore  a  leading 
part  in  influencing  the  views  of  naturalists  in  America 
in  regard  to  the  Darwinian  theory. 


452  A  CENTURY  OF  SCIENCE 

Dr.  Gray  soon  put  the  Darwinian  hypothesis  to  a 
severe  test.  In  the  Journal  for  1840  he  had  called  atten- 
tion to  the  remarkable  similarity  which  exists  between 
the  flora  of  Japan  and  a  part  of  the  temperate  portion  of 
North  America.  The  first  notice  of  this  subject  by  him 
occurs  in  a  short  review  of  Dr.  Zuccarini's  ***Flora 
Japonica/'  a  work  based  on  material  furnished  by 
Dr.  Siebold,  who  had  long  lived  in  Japan.  In  this 
review  (39,  175, 1840),  he  enumerates  certain  plants  com- 
mon to  the  two  regions,  and  says,  ^^It  is  interesting  to 
remark  how  many  of  our  characteristic  genera  are  repro- 
duced in  Japan,  not  to  speak  of  striking  analogous 
forms. "  In  a  subsequent  paper  (28, 187, 1859 ) ,  he  recurs 
to  this  subject,  and,  after  alluding  to  geological  data  fur- 
nished by  J.  D.  Dana,  he  says : 

*'I  cannot  resist  the  conclusion  that  the  extant  vegetable  king- 
dom has  a  long  and  eventful  history,  and  that  the  explanation 
of  apparent  anomaUes  in  the  geographical  distribution  of  species 
may  be  found  in  the  various  and  prolonged  climatic  or  other 
vicissitudes  to  which  they  have  been  subject  in  earlier  times; 
that  the  occurrence  of  certain  species,  formerly  supposed  to  be 
peculiar  to  North  America,  in  a  remote  or  antipodal  region, 
affords  in  itself  no  presumption  that  they  were  originated  there, 
and  that  interchange  of  plants  between  eastern  North  America 
and  eastern  Asia  is  explicable  upon  the  most  natural  and  gener- 
ally received  hypothesis  (or  at  least  offers  no  greater  difficulty 
than  does  the  arctic  flora,  the  general  homogeneousness  of  which 
round  the  world  has  always  been  thought  compatible  with  local 
origin  of  the  species)  and  is  perhaps  not  more  extensive  than 
might  be  expected  under  the  circumstances.  That  the  inter- 
change has  mainly  taken  place  in  high  northern  latitudes,  and 
that  the  isothermal  lines  have  in  earlier  times  turned  northward 
on  our  eastern  and  southward  on  our  northwest  coast,  as  they 
do  now,  are  points  which  go  far  towards  explaining  why  eastern 
North  America,  rather  than  Oregon  and  California,  has  been 
mainly  concerned  in  this  interchange,  and  why  the  temperate 
interchange,  even  with  Europe,  has  principally  taken  place 
through  Asia.'' 

This  paper  was  communicated  in  1859,  on  the  eve  of 
the  publication  of  Darwin's  ** Origin  of  Species. '^  At  a 
later  date  he  applied  the  Darwinian  theory  to  the  possi- 
ble solution  of  the  problem,  and  came  to  the  conclusion 
that  the  two  floras  had  a  common  origin  in  the  Arctic 


a.  jr. 


ayn^\^^ 


From  "  Life  and  Letters  ot  Charles  Darwin"  by  Francis  Darwin. 


DEVELOPMENT  OF  BOTANY  SINCE  1818     453 

zone,  during  the  Tertiary  period,  or  the  Cretaceous  which 
preceded  it,  and  the  descendants  had  made  their  way 
down  different  lines  toward  tlie  south,  the  species  vary- 
ing under  different  climatic  conditions,  and  thus  exhib- 
iting similarity  but  not  absolute  identity  of  form.  Before 
the  American  Association  for  the  Advancement  of  Sci- 
ence, in  his  Presidential  address,  in  1872,  he  used  the 
following  language : 

*' According  to  these  views,  as  regards  plants  at  least,  the 
adaptation  to  successive  times  and  changed  conditions  has  been 
maintained,  not  by  absolute  renewals,  but  by  gradual  modifica- 
tions. I,  for  one,  cannot  doubt  that  the  present  existing  species 
are  the  lineal  successors  of  those  that  garnished  the  earth  in  the 
old  time  before  them,  and  that  they  were  as  well  adapted  to 
their  surroundings  then,  as  those  which  flourish  and  bloom  around 
us  are  to  their  conditions  now.  Order  and  exquisite  adaptation 
did  not  wait  for  man's  coming,  nor  were  they  ever  stereotyped. 
Organic  Nature — by  which  I  mean  the  system  and  totality  of 
living  things,  and  their  adaptation  to  each  other  and  to  the 
world — with  all  its  apparent  and  indeed  real  stability,  should 
be  likened,  not  to  the  ocean,  which  varies  only  by  tidal  oscilla- 
tions from  a  fixed  level  to  which  it  is  always  returning,  but 
rather  to  a  river,  so  vast  that  we  can  neither  discern  its  shores 
nor  reach  its  sources,  whose  onward  flow  is  not  less  actual 
because  too  slow  to  be  observed  by  the  ephemerge  which  hover 
over  its  surface,  or  are  borne  upon  its  bosom." 

Gray's  active  interest  in  the  Journal  continued  until 
the  very  end  of  his  life.  There  were  many  critical 
notices  from  his  pen  in  1887.  His  last  contribution  to  its 
pages  was  the  botanical  necrology,  which  appeared  post- 
humously in  volume  35,  of  the  third  series  (1888).  His 
connection  with  the  Journal  covered,  therefore,  a  period 
of  more  than  a  half  a  century  of  its  life.^ 

The  changes  that  were  wrought  in  botany  by  the 
application  of  Darwinism  were  far  reaching.  Attempts 
were  promptly  made  to  reconstruct  the  system  of  botan- 
ical classification  on  the  basis  of  descent.  The  more  suc- 
cessful of  these  endeavors  met  with  welcome,  and  now 
form  the  groundwork  of  arrangement  of  families,  genera, 
and  species,  in  the  Herbaria  in  this  country,  in  the  man- 
uals of  descriptive  botany,  and  in  the  text-books  of  higher 
grade.     This   overturn  did  not  take  place  until  after 


454  A  CENTURY  OF  SCIENCE 

Gray's  death,  although  he  foresaw  that  the  revolution 
was  impending. 

One  of  the  most  obvious  changes  was  that  which  gave 
a  high  degree  of  prominence  in  American  school  treatises 
to  the  study  of  the  lower  instead  of  the  higher  or  flower- 
ing plants,  these  latter  being  treated  merely  as  members 
in  a  long  series,  and  with  scant  consideration.  But  of 
late  years,  there  has  been  a  renewed  popular  interest  in 
the  phsenogamia,  leading  to  a  more  thorough  investiga- 
tion of  local  floras,  and  also  to  the  examination  of  the 
relations  of  plants  to  their  surroundings.  The  results 
of  a  large  part  of  this  technical  work  are  published  in 
strictly  botanical  periodicals  and  now-a-days  seldom  find 
a  place  in  the  pages  of  a  general  journal  of  science. 

Cryptogamic  Botany  in  the  Journal  since  1846, 

In  glancing  rapidly  at  the  First  Series  it  has  been  seen 
that  a  fair  share  of  attention  was  early  paid  by  the  Jour- 
nal to  the  flowerless  plants.  So  far  as  the  means  and 
methods  of  the  time  permitted,  the  ferns,  mosses,  lichens, 
and  the  larger  algae  and  fungi  of  America  were  studied 
assiduously  and  important  results  were  published,  chiefly 
on  the  side  of  systematic  botany. 

The  Second  Series  comprises  the  years  between  1846 
and  1871.  In  this  series  one  finds  that  the  range  of* 
cryptogamic  botany  is  much  widened.  Besides  inter- 
esting book  notices  relative  to  these  plants,  there  are  a 
good  many  papers  on  the  larger  fungi,  on  the  algae,  and 
mosses.  Here  are  contributions  by  Curtis,  by  Ravenel, 
by  Bailey,  and  by  Sullivant.  The  lichens  are  treated  of 
in  detail  by  Tuckerman,  and  there  are  some  excellent 
translations  by  Dr.  Engelmann  of  papers  by  Alexander 
Braun.  Some  of  the  destructive  fungi  are  considered,  as 
might  well  be  the  case  in  the  period  of  the  potato  famine. 
It  is  in  these  years  that  one  first  finds  the  name  of 
Daniel  Cady  Eaton,  who  later  had  so  much  to  do  with 
developing  an  interest  in  the  subject  of  ferns  in  this 
country.  He  was  a  frequent  contributor  of  critical 
notices. 

Cryptogamic  Botany,  as  it  is  now  understood,  is  a 
comparatively  modern  branch  of  science.     The   appli- 


DEVELOPMENT  OF  BOTANY  SINCE  1818     455 

ances  and  the  methods  for  investigating  the  more  obscure 
groups,  and  especially  for  revealing  the  successive  stages 
of  their  development,  were  unsatisfactory  until  the  latter 
half  of  the  last  century.  Gray  recognized  this  condition 
of  affairs,  and  appreciated  the  importance  of  the  new 
methods  and  the  better  appliances.  Therefore  he  viewed 
with  satisfaction  the  pursuit  of  these  studies  abroad  by 
one  of  his  students  and  assistants,  William  G.  Farlow. 
Dr.  Farlow  carried  to  his  studies  under  DeBary  and 
others  unusual  powers  of  observation  and  great  indus- 
try. He  speedily  became  an  accomplished  investigator  in 
cryptogamic  botany  and  enriched  the  science  by  notable 
discoveries,  one  of  which  to-day  bears  his  name  in  botan- 
ical literature.  On  his  return  to  the  United  States, 
Farlow  entered  at  once  upon  a  successful  career  as  an 
•inspiring  teacher  and  a  fruitful  investigator.  He 
became  a  frequent  contributor  to  the  Journal,  keeping  its 
readers  in  touch  with  the  more  important  additions  to 
cryptogamic  botany.  He  had  wisely  chosen  to  deal  with 
the  whole  field,  and  consequently  he  has  been  able  to  pre- 
serve a  better  perspective  than  is  kept  by  the  extreme 
specialist.  The  greater  number  of  cryptogamic  botanists 
in  this  country  have  been  under  Professor  Farlow 's 
instruction. 

Systematic  and  Geographical  Botany  of  Late  Years, 

The  usefulness  of  the  Journal  in  descriptive  systematic 
botany  of  phanerogams  is  shown  not  only  by  its  accept- 
ance of  the  leading  features  of  DeCandolle's  Phytog- 
raphy,  where  very  exact  methods  are  inculcated,  but  by 
the  very  numerous  contributions  by  Sereno  Watson  and 
others  at  the  Harvard  University  Herbarium,  as  well  as 
from  private  systematists.  It  is  in  the  pages  of  the 
Journal  that  one  finds  the  record  of  much  of  the  critical 
work  of  Tuckerman  and  of  Engelmann,  in  interesting 
Phanerogamia.  Of  late  years  the  Journal  has  had  the 
privilege,  of  publishing  a  good  deal  of  the  careful  work  of 
Theo  Holm,  in  the  difficult  groups  of  CjnP^raceae,  and  also 
his  admirable  studies  in  the  morphology  and  the  anatomy 
of  certain  interesting  plants  of  higher  orders. 

Attention  was  called,  in  passing,  to  Gray  *s  deep  inter- 


456  A  CENTURY  OF  SCIENCE 

est  in  geographical  botany.  In  this  important  branch, 
besides  his  contributions,  one  finds,  among  many  others, 
snch  papers  as  LeConte's  ^*  Flora  of  the  Coast  Islands  of 
California  in  Relation  to  Recent  Changes  of  Physical 
Geography'*  (34,  457,  1887),  and  Sargent's  ^^ Forests  of 
Central  Nevada"  (17,  417,  1879).  Examination  reveals 
a  surprising  number  of  communications  which  bear  indi- 
rectly upon  this  subject. 

Paleontological  Botany » 

"When  the  Journal  began  its  career,  the  subject  of  fossil 
plants  was  very  obscure.  Brongniart's  papers,  espe- 
cially the  Journal  translations,  enabled  the  students  in 
America  to  undertake  the  investigation  of  such  fossils 
and  the  results  were  to  a  considerable  extent  published 
in  the  Journal.  Since  the  subject  belongs  as  much  to 
geology  as  to  botany,  it  finds  its  appropriate  home  in  the 
pages  of  the  Journal.  The  recent  papers  on  this  topic 
show  how  great  has  been  the  advance  in  methods  and 
results  since  the  early  days  of  the  Journal's  century. 
Under  the  care  of  George  R.  Wieland,  the  communica- 
tions and  the  bibliographical  notices  of  paleontological 
treatises  show  the  progress  which  he  and  others  are  mak- 
ing in  this  attractive  field. 

Economic  Botany,  Plant  Physiology ,  etc* 

At  the  outset,  the  Journal,  as  we  have  seen,  devoted 
much  attention  to  certain  phases  of  economic  botany,  and, 
even  down  to  the  present,  it  has  maintained  its  hold  upon 
the  subject.  The  correspondence  of  Jerome  Nickles  from 
1853  to  1867  brought  before  its  readers  a  vast  number  of 
valuable  items  which  would  not  in  any  other  way  have 
been  known  to  them.  And  the  Journal  dealt  wisely  with 
the  scientific  side  of  agriculture,  under  the  hands  of  S.  W. 
Johnson  and  J.  H.  Gilbert,  and  others,  placing  it  on  its 
proper  basis.  This  work  was  supplemented  by  Norton's 
remarkable  work  in  the  chemistry  of  certain  plants,  the 
oat,  for  example,  and  certain  plant-products.  In  fact  it 
might  be  possible  to  construct  from  the  pages  of  the 
Journal  a  fair  synopsis  of  the  important  principles  of 
agronomy. 


DEVELOPMENT  OF  BOTANY  SINCE  1818     457 

Physiology  has  been  represented  not  only  by  the 
studies  which  had  been  inaugurated  and  stimulated  by  the 
Darwinian  theory,  such  as  the  cross-fertilization  and 
the  close-fertilization  of  plants,  plant-movements,  and 
the  like,  but  there  have  been  a  good  many  special  com- 
munications, such  as  Dandeno  on  toxicity.  Plowman  on 
electrical  relations,  and  ionization,  and  W.  P.  Wilson  on 
respiration. 

There  are  many  broad  philosophical  questions  which 
have  found  an  appropriate  home  in  the  Journal,  such  as 
**The  Plant-individual  in  its  relation  to  the  species'' 
(Alexander  Braun,  19,  297,  1855;  20,  181,  1855), 
and  **The  analogy  between  the  mode  of  reproduc- 
tion in  plants  and  the  alternation  of  generations 
observed  in  some  radiata"  (J.D.Dana,  10,341,  1850). 
Akin  to  these  are  many  of  the  reflections  which  one 
finds  scattered  throughout  the  pages  of  the  Journal, 
frequently  in  minor  book-notices.  As  might  be  expected, 
some  attention  has  been  paid  to  the  very  special  branch  of 
botany  which  is  strictly  called  medical.  For  example, 
early  in  its  history,  the  Journal  published  a  long  treatise 
by  Dr.  William  Tully  (2,  45,  1820),  on  the  ergot  of  rye. 
This  is  considered  from  a  structural  as  well  as  from  a 
medical  point  of  view  and  is  decidedly  ahead  of  the  time 
in  which  it  was  written.  There  are  a  few  references  to 
vegetable  poisons,  and  there  is  a  fascinating  account  of 
the  effect  of  the  common  white  ash  on  the  activities  of 
the  rattlesnake.  In  short  it  may  be  said  that  the  editor 
did  much  towards  making  the  Journal  readable  as  well 
as  strictly  scientific. 

The  list  of  reviewers  who  have  been  permitted  to  use 
the  pages  of  the  Journal  for  notices  of  botanical  and 
allied  books  in  recent  years  is  pretty  long.  One  finds  the 
initials  of  Wesley  R.  Coe,  George  P.  Clinton,  Arthur  L. 
Dean,  Alexander  W.  Evans,  William  G.  Farlow,  George 
L.  Goodale,  Arthur  H.  Graves,  Herbert  E.  Gregory, 
Lafayette  B.  Mendel,  Leo  F.  Rettger,  Benjamin  L.  Robin- 
son, George  R.  Wieland,  and  others. 

At  the  present  time,  in  the  biological  sciences,  as  in 
every  department  of  thought,  there  is  great  specialization, 
and  each  specialty  demands  its  own  private  organ  of 


458  A  CENTURY  OF  SCIENCE 

publication.  Naturally  this  has  led  to  a  falling  off  in  the 
botanical  communications  to  the  Journal,  but  it  cannot  be 
forgotten  that  the  history  of  North  American  Botany  has 
been  largely  recorded  in  its  pages. 


Notes, 

*  Scientific  Papers  of  Asa  Gray.     Selected  by  Charles  Sprague  Sargent. 
Two  volumes,  Boston,  1889    (see  notice  in  vol.  38,  419,  1889). 

*  A  notice  of  Gray 's  life  and  works  is  given  by  his  life-long  friend,  J.  D. 
Dana,  in  the  Journal  in  1888  (35,  181-203). 


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